'91 F150 4X4 4.9 L dead

[brewster340]

Hello, new here.
My F150 died the other day. Zero power, no dome light, dash lights etc.
battery has a good charge, but everything is lifeless.
Where do I start?
regards

[discnik]

How old is your battery ? I had one that was only six years old looked good tested fine, load tested fine, but would drag when cranking. Replaced battery no more drag. Look for corrosion on and in your main positive battery cable. Check your ground cable for the same thing and make sure all mating surfaces are clean and tight. Most of the time it is the simple things. Good luck.

[rhandwor]

Clean the battery terminals first then look by the starter for a burned fuseable link.

[brewster340]

Originally Posted by discnik

How old is your battery ? I had one that was only six years old looked good tested fine, load tested fine, but would drag when cranking. Replaced battery no more drag. Look for corrosion on and in your main positive battery cable. Check your ground cable for the same thing and make sure all mating surfaces are clean and tight. Most of the time it is the simple things. Good luck.

The first thing I looked for was a poor ground.Looks good to me.
So let's exclude that for now.What else besides that would cause COMPLETE failure of power delivery? There is absolutely no sign of life. The dome light, marker lights etc. are not part of the ignition system, but everything is dead.
There is enough charge in the battery to power the dome light without question.
Thank you for your input.

[brewster340]

Originally Posted by rhandwor

Clean the battery terminals first then look by the starter for a burned fuseable link.

Oh yes, a burned fusible link. That is what I'm thinking. But where are they?
Apparently they are wrapped with electrical tape. If to much current passes through it the copper wire melts as it is thinner than the rest of the copper.
Can you please explain 'FUSABLE LINKS' in laymans terms? Where will I find them on this particular vehicle? I'm thinking around the fender mounted solenoid in particular. I know they need to be spliced back together if blown, but thats about it.
regards,
Paul

[GNRAxlRose88]

I don't know if it helps much, but my fullsize Bronco used to do this. The negative battery cable was loose at the battery terminal. I wold turn it over and the sylinoid on the fender would click and everything would go dead, i'd wiggle the cable and it would click again. I snipped the end of the cable, restripped it, and restraightened it and it was good as new.

[rhandwor]

I'm not sure what year they changed but the hook up to the starter. They are different colors on a ford. When they go they are burnt with the insulation burned off very easy to find. I used to keep a few in the garage that I cut off on a junk yard parts trip. Basically they are two wire sizes smaller than the supply wires so you could make one if needed just get some wire at the parts store. Cut off a piece of the larger diameter for reference. Use silicon to coat all wire splices to prevent corrision.

[brewster340]

thanks axlrose & rhandwer.
right now the truck is frozen solid and covered in 40 cm of snow, and it's always dark.
at first opportunity i'll remove both positive and negative cables for 'microscopic' inspection. i'll also make sure all connections are clean and tight.
and i'm buying a new battery with lots of cranking power. the old one is old and weak. the solenoid to starter wiring is also coming out for inspection.
i'll post my findings.
regards opcorn:

[brewster340]

well i finally got back to investigating why the darn thing won't start.
it still won't. without a doubt the battery is good, the starter is good, the positive and negative cables are good. by switching some wires around on the fender mounted solenoid i now have power, but it will not crank.
all connections/terminals are good.i used a screwdriver to cross the solenoid terminal to ignition terminal and it still won't crank,thus by-passing a solenoid problem. (i think)
so that leaves what? anyone?
i was wondering, what if i remove all wiring to solenoid and just have the neg. and pos. cables connected to solenoid and to starter and ground and cross solenoid pos. to solenoid ignition. it should at least crank, right? by doing this it would omit any problem that may be in the wiring system, such as the neutral lock out switch,etc.(standard trans.)???

[bobalue1000]

Check your clutch/start switch under dash. Use volt meter and check for voltage at starter when key is turned on in the start position.

[brewster340]

bobalou1000, yes, i was under there looking at the clutch switch, don't have a multimeter or any electrical testing equipment, but i've requested a auto/electrical manual from the library, then i can determine what equipment to buy and how to use it.
there is a reason i want to bypass all electrical systems in chasis and engine, to see if the starter will crank the engine first,before i go on a wild goose chase.it could be ignition switch or any number of things.burnt fuselink etc.,
process of elimination is what i'm trying to do.
tks.

[rhandwor]

If its just two wire you can jump this (bypass) for testing) just make sure the clutch is pushed in when doing this test.

[brewster340]

thanks for the heads up, don't want the truck lurching forward if it cranks.
I'll just block the wheel and put trans. in neutral.

[FNA]

"without a doubt the battery is good" says the man who also says "[i] don't have a multimeter or any electrical testing equipment"

Seat of your pants mechanics is all well and good, but spend the $15 and buy a multimeter if you want to do electrical work.

No matter what you do to diagnose this problem, no matter where you look, without some sort of electrical tester (make a test light at home, it's a kid's project), you are doing it the worst and most unreliable way.

[brewster340]

FNA you pompous a-hole. if i was an electrical diagnostic expert like you apparently are, i would not have asked, would i ?
i already bench tested the starter and tested the battery.
if you can't be of any help, then piss-off!