Headlight fix

[MrPink]

Hi, everyone.

My '96 has been plagued with the "intermittent headlamp/burned fusebox connector" problem for awhile, and I have finally gotten around to fixing it.

The contacts for the fusebox headlight circuit connector oxidize and fail. This is a vicious cycle, because as the contact oxidizes, its resistance goes up. As resistance goes up, more heat is created in the contact, and the contact oxidizes further. And so on.

Here's what I did:

If your headlights have not failed yet, you can stop this dead in its tracks by doing a couple of things. First, pull the headlamp fuse. Then, find the connector. It's located on the firewall side of the fusebox, and it's the connector closest to the brake pedal on that edge. Pull it apart and inspect it. If you see no signs of burning you are almost gold. Squirt a bit of WD-40 or LPS-1 into the connector socket on the fuse box. Next, take a small screwdriver and collapse the contacts on the connector a bit so that they will make better contact with the copper blades in the fusebox. Squirt WD-40 on the contacts in the connector, too. Now, put it all back together. Pull it off and push it on a couple of times. Done.

If you find oxidation but little or no heat damage on the blade/plastic, you are still almost gold. You'll just need to clean the oxidation off of the copper blade before doing the above. I use a dentist's tool (the same one they scrape tartar off with when the cute hygienist does your teeth) to do that. Don't have one? Ask your dentist. They are always scrapping these things out when they get too worn to sharpen again. Or, you can use some other tool, like a eXact-O knife. The objective is to get that copper nice and shiny again. I haven't looked at the schematic to see if any of those other pins are hot, so don't touch any of them with your metal tool!! Want to be really safe? Wrap a bit of 400-grit wet/dry sandpaper on a popsicle stick and clean with that. Then, do the WD-40 and tighten thing above, and again, you're done.

Oh... your connector is burned and cruddy... like mine was? Here's what you do.

You have to remove the fuse box assembly. Take all the connectors off of the front, first. Then, remove the top screw on the bracket. For the bottom bracket, remove it from the vehicle floor by taking off that little plastic capnut that holds the trim piece and the fusebox bracket to a stud sticking out of the floor. Leave it attached to the fusebox. If you take the bottom screw off instead, it's difficult to put it all back together later because of tensions and crummy fit. This way is easier.

Next, remove all the back connectors. The one on the side of the box will need to be finessed off with a small screwdriver to get it off of the locking tab. Don't worry about marking connectors. Each one is different.

Now remove the box. It should look like this (well, yours will still have the copper pin there. This was taken after I already removed it- nice hole, Pink!):



Now, you want to remove a bit of the plastic from the back side of the fusebox assembly so that you can get to a good piece of copper for that terminal. I used a razor saw and fine diagonals to expose what I needed, and ended up with this:



This photo shows the cutaway and the copper buss already cleaned and tinned with solder. (You can also see a small notch I cut on the side for the new wire to stick out of.) We are going to lap-solder a nice big piece of wire to that spot. You will need to remove the plastic to expose the copper, clean the surface, and tin it with solder. You also want to snip away (from the bottom) that burned portion of copper that sticks up where the connector used to push onto it. We don't need it anymore, and it will just be in the way.

I used a spade-lug and spade-lug Faston to fix this connection. You can use any sort of connector you want, but it needs to be able to handle 10A or so of current.

Take a 4" or so piece of 12-gauge wire. Attach the spade-lug to one end. You can crimp, but I suggest soldering this, instead. Next, strip about 1/4" of insulation from the other end of the wire. Tin this with solder. Now, we are going to use a technique called lap-soldering to make this connection.

The easiest way to do this is to have a little bit of extra flux lying around. I have a bottle of liquid rosin (Radio Shack has flux) for just this sort of purpose, but you can use paste or anything else, as long as it's for electronic work and not acidic (NO PLUMBING FLUX!!) The idea of lap-soldering is to make a fillet of solder along two surfaces. We tin both, we apply a bit of flux to both, we add a bit more solder to the tip of the iron, we heat the joint.

So- make sure the buss and wire are tinned, add your flux, add a bit of solder to the tip, and lay the wire flat on the buss. Now heat, and hold. The solder will flow nicely because of the flux, and the joint will be smooth and strong. Easy.

Too much trouble? Just solder it normally, then. But it's difficult to hold everything together and solder normally at the same time. You need three hands (or a cute hygienist!).

Once you have it soldered, it should look something like this:



Next, fill the area back up with hot-melt glue (adds strength back, stops vibration fatigue and more importantly, INSULATES!), and add a little extra along the wire and solder joint to get this:



The last thing I did (not shown in the above photo) was to add a piece of sleeving to cover up the new connectors when you put it all together to keep them from shorting out on something. I used a piece of wire heat-protection fabric tubing that I yanked from an old microwave oven and hot-melted it onto the wire with the spade on it. This way, when joined, the Faston and spade are covered completely by the tube. You can use anything you want, or you can simply tape everything up once assembled if you don't want to take this step.

The next thing you have to do is put the Faston onto the wire that's coming out of the connector. All you need to do here is snip the wire off of the connector (you can leave the metal part inside the connector) and attach the Faston to it. Again, you can crimp, but I like a soldered connection much better. I cannot caution you enough about one thing, here:

MAKE SURE YOU CUT THE CORRECT WIRE!!! You don't get a second chance.

This is the repair, with the connector pulled out of the fusebox. You can see the protective sleeve I glued onto the fusebox wire to make the connection short-proof:



And there you have it! Plug the connector back into the fusebox, make the repaired connection, and reinstall the headlight fuse. All done, and not too hard!

-Pink

EDIT: Typos. And... bizarre. Sometimes some lines wrap, and some don't. <shrugs>

[Johnny Mullet]

That is a wonderful headlamp diagnostic guide. Thanks

[carpenter_jai]

This is awesome! I tried to do something like this, with the exception of leaving out the hot melt glue. Wish I had used it cause the solder joint just came apart. I also tried drilling through the copper in the fuse block, inserting the wire through this hole and soldering the connection. It lasted for a month and a half. When I fix it next time, I am using your method.

[Hugemoth]

I solved the problem once and for all by using relays to switch the power directly from the battery to the lights. The switch, fuse box, wiring, etc., now only carry the current to switch the relays, a few milliamps. An added bonus is instead of a measured 11.4 volts at the lights, there is now full battery voltage, about 14.2. The lights are much brighter.

Q

[carpenter_jai]

Hugemoth, I remember a previous thread where you explained this modification. I want to do it.

I have only a little electrical repair experience. I was able to rewire my rear tail lights. I still don't understand how to add a circuit to the fuse block. If somebody could explain to me how to identify what is a good constant power source to wire into, I'd appreciate that.

I would love more information on how to add a relay. Mainly I am unsure of which wires to make the splices at.

Sorry for my ignorance, but we all need to learn how to do this at some point.

Jai

[Hugemoth]

Jai,

No need to add a circuit to the fuse box as all the wiring required to add relays is done up front next to the battery. After the relays are in place the headlight circuit in the fuse box and the switch only carry the small amount of current needed to activate the relays. I haven't drawn a wiring diagram but it is quite simple when you understand how the relays operate. What you're doing is cutting the wires at the headlights and connecting the headlights to the relays. You're using the wires that used to feed current to one headlight to trip the relays. One relay for low beam, one for high beam. A wire with inline fuse is connected directly to the battery terminal to power the lights.

Q

[ydeardorff]

First of all thank you, Im going to dive into this mod today.

[ydeardorff]

I found simply cutting the white wire with the black stripe, and putting a large female spade connector on it, then plugging it into the 3 pin connector, in the slot that's 90 degrees to the other two.
Internally this is directly connected to the burnt terminal, but is 6 times bigger.

As soon as I did this, everything worked perfectly. DRL's, low beams, and high beams.

[ydeardorff]

Even with the fix I did, that lights are tons brighter, but that same DRL issue is there. Im instaling my HID's this weekend, can you tel me where I shut these bastards off forever without effecting the headlights? The HID's use there own power source, and use only one headlight connector. So I only need to disable the DRL's without affecting the headlight circuits.

[cjofwolfcreek]

Ydeardoff, following your mod instructions, I ohmed out the burnt out connector pin to the unused 90 degree offset one in the three prong connector and sure enough I had continuity! Found a spade connector and crimped it on the short length of wire. It took a bit of pressing to get the new female spade into the plastic connector housing but I got it and spliced the other end of the wire into the black/white and for the first time in a long time, my headlights work! A few zip ties to ensure my big feet don't pull on those wires anymore and it's all set. Thanks for sharing your fix, it worked for me.

[jake1ekaj]

I have been driving on the DRLs for over a year now because of this issue. At one point on a trip I was smelling the acrid burnt electric smell, but never seemed to figure out the issue. Then a month or so later the head lights quit working. Dur!!!

So, now that I got everything done around the house and I'm fixing to move back to NY, where they inspect the hell out of you, I figured I better get this under control.

I whipped out the service manual and followed thier trouble tree and found this junction block connector C3 cavity 3 wire/pin were toast. The trouble pin here as above. Looking at the schematic in the manual, it appeared to be the issue. My pin doesn't look as burnt as yours above, but for the low price of $10, I got another fuse block/junction block from the pull-a-part. Even on the new one it appears to have gotten a little "warm" but even lesser than mine. I will clean the snot out of the connectors and reassemble with dielectric grease.

I guess I should have searched on here a long time ago, nice pics BTW.

Thanks for the informative post.

Jake

[jake1ekaj]

Reassembled and problem solved, sweet!!!