I need HELP!! Lights switch and ignition??

[paolotvl]

Hello everybody, thank you for reading this.

I'm new to the forum, I've had my first truck for about one year, it is a 1987 Custom Deluxe 5.7 V8 4x4. I've had a problem for a few months, which is the engine would die when you turn the lights on. Then it would take anywhere from one to ten minutes to start again. I did some research and thought that the negative wire of the battery was bad. So I replaced that. I thought I solved the problem because the problem disappeared for a few weeks. The other day it did it again. So I thought it might be a bad light switch. I ordered a new one and I just replaced it. The funny thing is that:
1- when I removed the original the lights stayed on. It took me about 15 minutes to replace it. I was alone so I thought, worst case I'll have to recharge the battery.
2- sometime while I was under the dash cussing the lights stopped working.
3- I replaced the switch, tried to start the truck and it cranks fine ( so the battery is working) but the engine doesn't fire up.
4- no light is currently working. I swapped the switch with the old and sa e problem: no lights and the engine cranks fine but doesn't start.

I'm lost. Any ideas??

 

[paolotvl]

The more I think about this, the more I think it is some sort of a coincidence. How do you check if the fuse box is well connected? Can it be a short I. The light system? What can completely kill all the lights and still getting the engine to crank and not fire up?


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[paolotvl]

I just checked (in the dark with a maglite) and the wire connectors on the engine side on the firewall are completely covered in dust and very brittle... How difficult it is to rewire one of these trucks??

 

[350runner]

It's only hard as you make it it really sounds like something in the light system is grounding out. @chengny usually has some insight on things like this.

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[paolotvl]

Thank you!! I'm really depressed right now....I can tackle any mechanical problem but electrical problems really scare me...and I can't take the truck to a shop if it doesn't start.... Since it got dark outside, I could not see very well so I used my iPhone to shot some random pictures under the dash to get an idea of the situation and it does not look pretty. That is when I started thinking about replacing the entire wire harness....


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[paolotvl]

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[paolotvl]

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[Boone83K10]

Your fuse box doesn't look any different than every other pic of a fuse box I have ever seen of these trucks. Really you should take a pic of the wires at the light switch, then we can go from there.

 

[paolotvl]

Here it is:

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[paolotvl]

And this is the wire connection on the firewall:

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[paolotvl]

I did spray some wire dryer on these


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[350runner]

And this is the wire connection on the firewall:

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This is normal. GM used that gooey stuff as a sealant .

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[paolotvl]

Tomorrow I have time to work on it... I need to start testing wire by wire?? I do have a test meter. One of the many things that doesn't make sense to me right now is: if it is a short somewhere...shouldn't it just blow a fuse? Are ALL the lights on the same circuit?


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[350runner]

Start with the light circuit unplug the head lights then pull the head light switch out to the on position. Are you still having this issue? I'll check back tomorrow..

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[paolotvl]

Thank you for the help!!!! I really appreciate it!!!


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