replacing battery terminals/wire nest

[sixleggedinsect]

i have been having corrosion problems for a long time with my battery, and finally the car is having trouble starting. i am assuming this is a problem with the very corroded + terminal.

however, before i just rip everything off and start over, i want to make sure i know waht im doing.

the terminal clamp has two large wires coming off it. one has a small black plastic box thing with two smaller wires coming out of it. this whole assembly is very corroded and i would like to snip all the old wire out and solder in new stuff.

what does that black plastic box do? is there something inside? a fuse? can i just replace the whole nest with nice new wiring?

thanks,
anthony

[MT-2500]

Originally Posted by sixleggedinsect

i have been having corrosion problems for a long time with my battery, and finally the car is having trouble starting. i am assuming this is a problem with the very corroded + terminal.

however, before i just rip everything off and start over, i want to make sure i know waht im doing.

the terminal clamp has two large wires coming off it. one has a small black plastic box thing with two smaller wires coming out of it. this whole assembly is very corroded and i would like to snip all the old wire out and solder in new stuff.

what does that black plastic box do? is there something inside? a fuse? can i just replace the whole nest with nice new wiring?

thanks,
anthony

You will be better off to get the OEM type battery cables to start with and replace the hole cable instead of he add on ends.
And if old battery is spitting out juice check it or replace it.
And put some terminal protection on the new stuff.

[sixleggedinsect]

Originally Posted by MT-2500

You will be better off to get the OEM type battery cables to start with and replace the hole cable instead of he add on ends.

thanks for the reply, but that may not be an option.

any idea what that black plastic contraption on the positive battery line is?

[MT-2500]

Originally Posted by sixleggedinsect

thanks for the reply, but that may not be an option.

any idea what that black plastic contraption on the positive battery line is?

Not without looking at it.
If you can post a picture we will look at it.
Could it just be the plastic cover for it?

[Selectron]

I can't help in identifying the black box on the positive terminal - I also have one but I've never had reason to check what purpose it serves - it may be different on my model anyway, because mine is a UK diesel-engined Escort. While I'm here though, I'll make a few points about your battery in general.

If you've been having corrosion problems at the terminals for a while, then the battery may be being over-charged (and therefore producing excessive gases, thereby causing the corrosion). If you have access to a multimeter, you might want to check the terminal voltage. With the engine running, it will probably be thirteen-point-something volts, maybe 14V and then when revving the engine, it should rise to around 14.4V (between 14.2V and 14.6V) and then stabilise at that voltage - that tells you that the voltage regulator is functioning correctly. If it continues to rise too far beyond that voltage, then the regulator would be suspect.

If you're having terminal corrosion problems, then that would suggest that it's the non-sealed type of battery, in which case be sure to check your electrolyte levels and top-up with distilled water as required, because the levels might be low.

Whichever method you use to repair the damaged leads, be sure to apply a protective coating to all connectors prior to reconnecting to the battery. Here in the UK, I use something called petroleum jelly, or Vaseline™, which is available for pennies from any pharmacy. I don't know what you would commonly use for that purpose if you're in the USA, but whatever it is, be sure to use some.

[sixleggedinsect]

alright, back to work..

Originally Posted by Selectron

If you've been having corrosion problems at the terminals for a while, then the battery may be being over-charged (and therefore producing excessive gases, thereby causing the corrosion). If you have access to a multimeter, you might want to check the terminal voltage.

i actually keep a pretty good eye on the voltage. its within normal ranges.

If you're having terminal corrosion problems, then that would suggest that it's the non-sealed type of battery, in which case be sure to check your electrolyte levels and top-up with distilled water as required, because the levels might be low.

Whichever method you use to repair the damaged leads, be sure to apply a protective coating to all connectors prior to reconnecting to the battery. Here in the UK, I use something called petroleum jelly, or Vaseline™,

yeah, i actually take care of both of those- although now that the car has been sitting aroudn a few months and looks terrible you obviousl woudln't know. i basically want to go back to square one and start over with pretty fresh terminals and wires that arent corroded and fasteners that still have corners for a hex wrench..

so- i finally got back to my car and took some photos. and i was wrong, the 'black box' is on the ground, not the positive. i am assuming it is some quick way for the factory to splice all the various grounds in together, as four or five various wires thread out of the box into various sensor wires, etc. i would like to take off the terminal, the box, and snip the wires, and just solder everything together with new stuff.

there are photos of the mysterious plastic thing here:

http://electricant.net/misc/temp/DSC00749.JPG
http://electricant.net/misc/temp/DSC00753.JPG

the big question is: is there anything inside that plastic black thing that needs to be there? a fuse? sensor? anything i cant just chuck?

thanks, as always..

anthony

[MT-2500]

It looks like just quick plug in connectors.
One big problem I see is battery corrosion all over.
Some time a battery gets old and leaks or throws out the acid.
I would consider a new battery and clean off corrosion and repair cables as needed.
MT

[sixleggedinsect]

Originally Posted by MT-2500

It looks like just quick plug in connectors.
One big problem I see is battery corrosion all over.
Some time a battery gets old and leaks or throws out the acid.
I would consider a new battery and clean off corrosion and repair cables as needed.
MT

hey folks. still havent gotten around to cleaning everything up- im still not dead sure what im dealing with, though. i spoke with a seemingly knowledgeable mech who said that little black box was part of the charging system. i was surprised to hear it. could i get a second opinion? (see links earlier in thread for photos)

also, ive been keeping an eye on the alternator voltage and it now seems to hover around 14.6= 14.8v. i always thoguht of 14.5 as the high end, and the previous poster mentioned 14.6. is this a alternator dependant number, or is mine definitely too high? and if it is higher than normal, does that matter? or shoudl i only be concerned if it stays at, say, 15.5v or something like that?

it woudl make my life a lot easier if i could get rid of that black plastic thing. surely someone has taken one off/apart and could comment..

thanks

[Bobbywolf]

That still isn't alarming. If your regulator in your alternator took a dump, you would be getting some high voltages. 15V+ which can cause your battery to boil if run too long, and ultimatly destroy it.

The corrosion you have looks like regular copper corrosion. Fluffy green crap. I'd get a wire brush and clean it all off the best you can to bare metal, and then use some dielectric grease, or even vasiline as previously mentioned to keep the moisture off of it. Check how well your ground is working by placing one end of the multimeter (in the lowest range of Ohms) on the negative terminal of the battery, and the other end on your engine block. You should have a number close to zero (2 or so is ok). Then try from the neg terminal to a bolt on the body (scratch that point just so you get good contact).

If you have a reading that is higher than a couple ohms, you have a grounding issue, which can cause all sorts of electronic/ electrical issues. As for replacing the ends, it may be a good idea, considering the amount of corrosion, but I honestly can't tell you what that box is on the neg terminal. However, mine also has it, so you are not alone!

[Selectron]

I wonder if that's a 1.9L? I have some service info for the 1995 Escorts and it shows the 1.9L as having the usual main ground connector, but then also two ancillary grounds, all connected at the battery negative terminal. Here's the diagram which states that it's the 1.9L only:



... and a zoom view:



That refers the reader to section 10-12, which is this:



... and a zoom view:




That shows the two ancillary ground connections but there's no reference to any actual circuitry at that point, so that model probably would be fitted with a simple junction box at the negative terminal. Bear in mind though that that's for the '95, and I think your model is a '93, for which I have no info.

The regulator output voltage will differ somewhat depending on vehicle manufacturer and on model, so the only way to be sure of the precise voltage to expect would be to look it up in either a Ford manual or possibly a Haynes or Chilton, etc.

I'd agree with Bobbywolf and say that 14.6V isn't alarmingly high although if I saw 14.8V then I'd start to investigate. A lot depends on the type of driving that you do. If it's mostly short runs around the city - stopping, starting, sitting idling at traffic lights etc. then the battery wouldn't get chance to overcharge, even if the regulator output was a little high. It would only be an issue if you did a lot of long-distance driving on the freeway, during which the battery charging voltage would be held too high for hours on end, which would indeed eventually overcharge the battery and cause problems.

I'd put that issue to one side for the moment though and concentrate instead on getting the corrosion cleared from the terminals - either clean them with a wire brush, or fit some new connectors, liberally smeared with dielectric grease. I'd say that any voltage readings which you take right now are pretty meaningless while the terminals are in that condition, so start with the basics and get it all cleaned up (also check the connections at the alternator) and then you may even find that the voltage readings will be different.

Edit: Actually, if you look at that last diagram, you can see that the two ancillary grounds branch out to become four separate grounds, and that may all happen right at that negative terminal junction box.

[sixleggedinsect]

Originally Posted by Selectron

I wonder if that's a 1.9L? I have some service info for the 1995 Escorts and it shows the 1.9L as having the usual main ground connector, but then also two ancillary grounds, all connected at the battery negative terminal.

That shows the two ancillary ground connections but there's no reference to any actual circuitry at that point, so that model probably would be fitted with a simple junction box at the negative terminal. Bear in mind though that that's for the '95, and I think your model is a '93, for which I have no info.

no, im afraid i mislead you with a recent post. i had a 93, but the one im driving now is a 97. 2.0L. your graphics didnt show up on my browser, for whatever reason, but ill have to look at the wires coming out of that thing again. it never occured to me to just hook them up to the multimeter.

do you guys (and gals?) think that if the resistance between all wires leaving the little black box is low to nothing, i can assume it is just a junction? what kind of resistance could i expect to see from wire to wire in a junction box, fat gauge cables, but probably some corrosion. 0.5 Ohm?

The regulator output voltage will differ somewhat depending on vehicle manufacturer and on model, so the only way to be sure of the precise voltage to expect would be to look it up in either a Ford manual or possibly a Haynes or Chilton, etc.

I'd agree with Bobbywolf and say that 14.6V isn't alarmingly high although if I saw 14.8V then I'd start to investigate. A lot depends on the type of driving that you do. If it's mostly short runs around the city - stopping, starting, sitting idling at traffic lights etc. then the battery wouldn't get chance to overcharge, even if the regulator output was a little high. It would only be an issue if you did a lot of long-distance driving on the freeway, during which the battery charging voltage would be held too high for hours on end, which would indeed eventually overcharge the battery and cause problems.

hmm. im the latter type. i pretty much leave my car sitting around for a week to a month, then drive it a few thousand miles on the highway. then let it sit..

but 'boiling out' the electrolyte? what is actually happening? can i just add a little acid or water later and everything will be fine? (out of curiosity)

I'd put that issue to one side for the moment though and concentrate instead on getting the corrosion cleared from the terminals - either clean them with a wire brush, or fit some new connectors, liberally smeared with dielectric grease. I'd say that any voltage readings which you take right now are pretty meaningless while the terminals are in that condition, so start with the basics and get it all cleaned up (also check the connections at the alternator) and then you may even find that the voltage readings will be different.

good call. thats the plan. ive read that plain old grease will work fine, and dielectric grease is not necessary. is this true? it would save me a few bucks and a trip.

thanks for your help, folks

[Arnoldtheskier]

I 'ld be planning for some MORE trouble with that kind of battery acid/corrosion. if you're lucky it will be a no-start. If not..that kind of corrosion can eat through wires..NO kidding. Probablly has with that You do not want to be driving along and suddenly have next to battery cable connection at the battery...or worse..it burning through.

Corrosion this bad has probablly eaten into the wire a lot futher up than you had planned. You're gonna have to cut it..peel back the insul..head up the wire to where it is good. And splice it there.

Pack the wire brush idea for now. You DO NOT want that stuff flying around..on your clothes,in your eyes..on stuff under the hood.Use a dry paper towel. Pick off most of it with that. Keep it in the towel. Then gently use a screwdriver or scraper or something. When you have almost all of it off. Use the wirebrush. That is not enough. Use some baking soda..some sort of cleaner. Now you can get to work fixing it.

A cheap way of splicing battery cables is to bare both the ends..mesh them together and use 2 of those small wire rope/cable clamps. Cover it with a piece of heater hose. Sometimes the price of oem battery cables is just not funny at all. HOW?? can ANY car part be SO overpriced!! Maybe hit a boneyard. Even the factory ends..you can use universals. Root around..you can find some ring terminals..attach them to a marine battery terminal or something.

After you're done..I would spray the previous bad areas with some contact cleaner. As for protection..best stuff I have found is that spray grease..that foams/gels up.

Then check BOTH ends of the main battery cables,grounds.

[Selectron]

First thing to say is that you can't measure resistance on a live circuit, so the battery positive terminal would need to be disconnected before taking resistance readings across the negative terminal junction box. I won't muddy the waters with a lengthy explanation of that but I will add a footnote about it, because it's an important point to be aware of when fault-finding on electrical/electronic circuits.

So, turning to the black box - if it is just a junction box then the resistance across it should be so low as to be outside the resolution of your meter, which is another way of saying that whatever reading you get when touching the meter probes directly together (typically 0.5 ohms or thereabouts), is the same reading that you should get when measuring across the junction box. You might at most see an increase of one digit on the least significant digit - say 0.5 ohms rising to 0.6 ohms. If that is what you find, and if you get the same reading when swapping the probe positions and measuring in the opposite direction, then you can safely conclude that it's a straight-through junction box.

Given the type of driving that you do - mainly long-distance highway driving - then I would definitely make a point of measuring the battery terminal voltage again after the clean-up operation and seeing if it's still sitting around the 14.6 to 14.8 mark. If it is, and if that's higher than the specified voltage then that would be a cause for concern. I'd make a point of checking a service manual to see what the acceptable range is for that particular model, and then I'd measure the voltage again using a different meter, just in case the meter is reading a little high.

I'm an electronics engineer by profession so I have a selection of multimeters here, and I also happen to have a spare battery in the kitchen so I'll check the voltage readings just out of curiosity.

Meter 1: 12.8V (old analogue [moving-coil] meter).
Meter 2: 12.96V (expensive, high-quality digital meter)
Meter 3: 12.97V (ultra-cheap, basic digital meter bought for a few pounds at the grocery store)

It's interesting that the two digital meters, though vastly different in terms of both quality and price, both record the same voltage to within one 1/100th of a volt.

Electronics is my specialist subject but what I know about chemistry would fit comfortably on the back of a postage stamp, so I can't explain the discharging/charging processes from a chemical point of view. My understanding though, has always been that it's never necessary to add acid except in the event of an accidental spillage. Under normal circumstances, when the electrolyte level falls, it's only necessary to top-up with distilled (mineral-free) water. One thing I can safely say (from experience) is that excessive charging will cause overheating of the electrolyte, leading to expansion of the lead plates (leading in turn to possible physical distortion and internal short-circuits) and also expansion of the electrolyte itself, and then evaporation of at least the water content of the electrolyte. I don't think it's simple water evaporation though, because the gases produced are generally reckoned to be highly corrosive, so any way you look at it, overcharging is bad news.

As for using regular grease on electrical connections - I've never tried it and nor can I recall ever seeing it recommended, and I've been maintaining my own motorcycles and cars for more years than I care to remember. I've never used proprietary dielectric grease either. I just keep a little tub of Vaseline™ petroleum jelly in my toolbox - it's available at any pharmacy or grocery store at a cost of pennies, and it has never failed me yet, over the course of many damp and dreary British winters.

Oh yes, and here are the direct links to those pictures which your browser wasn't displaying. Not that they will be relevant though if your model is a later 2.0 but somebody else may have a use for them, if the direct links work.

http://img206.imageshack.us/img206/1089/01vr9.png
http://img87.imageshack.us/img87/7623/02gk5.png
http://img87.imageshack.us/img87/8747/03du9.png
http://img83.imageshack.us/img83/6273/04sn9.png

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And now for that footnote about why one can't take resistance readings on live electrical circuits - not worth reading beyond this point unless you're particularly interested in matters electrical and electronic.

Multimeters, both analogue and digital, measure resistance by applying a voltage across two points in a circuit, via the meter probes. This causes a current to flow, and the magnitude of that current will be determined by the resistance between the two probes. It therefore follows that the value of the resistance can be derived according to Ohm's law, whereby:

V = I x R
I = V / R
R = V / I

... where V, I and R are voltage, current and resistance.

So, in the instance mentioned earlier, where we want to measure the resistance across the junction box, we would disconnect the battery positive terminal, and apply the meter probes across the junction box - this would cause a current to flow, and the meter would display the derived resistance (derived from the magnitude of the current).

So what happens if we don't disconnect the battery positive terminal? Well, there will already be a current flowing through the junction box even before we connect our meter - this would be the current which operates the vehicle clock, and the memory backup circuit for the radio station tuning presets, also possibly memory backup current for some of the myriad electronic control modules fitted to modern vehicles, and any leakage current which may be flowing in aged or faulty wiring or components. If we then apply a meter and try to take a resistance reading, the meter will respond to the sum of both currents - that which is derived via the meter probes, plus that which was already flowing in the circuit, and therefore the indicated resistance reading will be erroneous, and that's why it can't be done, so always disconnect one side of a circuit before attempting to take a resistance measurement.

There is also the secondary consideration that you may try to measure the resistance across a portion of the circuit where a relatively high voltage is present (checking resistances inside a TV set for example). On a modern digital meter, this would likely just result in an 'OL' (overload) indication, but in days of yore when moving-coil analogue meters were the norm, the same scenario would cause the needle to fly across the scale with considerable velocity and it could easily - and often would - destroy the meter. It's not a mistake that I've ever made myself but I have seen it happen. So for those of us such as myself who grew up using moving-coil meters, it's just second nature to automatically disconnect the power source before taking a resistance reading.

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[sixleggedinsect]

Originally Posted by Arnoldtheskier

I 'ld be planning for some MORE trouble with that kind of battery acid/corrosion. Corrosion this bad has probablly eaten into the wire a lot futher up than you had planned. You're gonna have to cut it..peel back the insul..head up the wire to where it is good. And splice it there.

(sigh). i know. thats why ive been going on since the beginning about wanting to strip out all the bad stuff and spice in new. and the junction box, or charge circuit device, or whatever it is, is well within the 'corrosion zone', if you will. thats why i wanted to cut that out too.

Pack the wire brush idea for now. You DO NOT want that stuff flying around..on your clothes,in your eyes..on stuff under the hood.Use a dry paper towel. Pick off most of it with that. Keep it in the towel. Then gently use a screwdriver or scraper or something. When you have almost all of it off. Use the wirebrush. That is not enough. Use some baking soda..some sort of cleaner. Now you can get to work fixing it.

i plan on hosing it down, then finishing up with a terminal brush and some baking soda if it looks necessary.

A cheap way of splicing battery cables is to bare both the ends..mesh them together and use 2 of those small wire rope/cable clamps. Cover it with a piece of heater hose. Sometimes the price of oem battery cables is just not funny at all. HOW?? can ANY car part be SO overpriced!! Maybe hit a boneyard. Even the factory ends..you can use universals. Root around..you can find some ring terminals..attach them to a marine battery terminal or something.

i wanted something a little burlier. i was planning on soldering- splicing cables, fluxing, and soldering with a propane torch. pretty sure i should be able to get my hands on one, even though im on the road. ive seen cables at walmart with ends installed for 5 bucks which i can use.

the crux of all this is what is that dang black box???

[sixleggedinsect]

Originally Posted by Selectron

First thing to say is that you can't measure resistance on a live circuit, so the battery positive terminal would need to be disconnected before taking resistance readings across the negative terminal junction box.

thanks for the good info. i have always wondered whether R readings on a live circuit were valid and never got around to finding out the answer. thank you.

Meter 1: 12.8V (old analogue [moving-coil] meter).
Meter 2: 12.96V (expensive, high-quality digital meter)
Meter 3: 12.97V (ultra-cheap, basic digital meter bought for a few pounds at the grocery store)

It's interesting that the two digital meters, though vastly different in terms of both quality and price, both record the same voltage to within one 1/100th of a volt.

the one i use is an old but at-the-time-expensive digital model by fluke. ill assume it is accurate enough for my purposes.

As for using regular grease on electrical connections - I've never tried it and nor can I recall ever seeing it recommended, and I've been maintaining my own motorcycles and cars for more years than I care to remember. I've never used proprietary dielectric grease either. I just keep a little tub of Vaseline™ petroleum jelly in my toolbox - it's available at any pharmacy or grocery store at a cost of pennies, and it has never failed me yet, over the course of many damp and dreary British winters.

well, the other poster mentioned spray grease. the spray greases ive seen are just plain old white greases. and you use vaseline. so it soudns like whatever i have lying aroudn will work. (incidentally, ive had little luck with vaseline in the past. i thoguht maybe it got too runny with underhood temps. thats partly why i wanted to use normal high-temp grease).

now if i could just figure out what that black plastic thing is.

im hoping to drive by a ford dealership where i can stop in and ask a mech.

thanks, all

anthony