Major Electrical Problem. Need Help Please.

[TSleid]

So i have a 1988 C1500 GMC and i'm having major electrical problems.

 

First off is my taillights. They work whenever they feel like it and my passenger side light is dim and when my brakes or left signal is applied the passenger side completely goes out. Also my reverse aren't working now either. Sometimes when it gets too cold or whenever they feel like it they cut out completely. Also randomly sometimes my right signal will stay solid and sometimes it will work and my wipers work on and off whenver they feel like it.

 

I'm so confused on what exactly this could be. maybe a bad ground? or maybe my command start is wired funky and is messing with my lights. I'm not sure but i need to fix it and don't know where to start.

 

So if someone could please help it'd be much appreciated.

 

 

Thanks

 

 

Tyler

[ChevyTech77]

So i have a 1988 C1500 GMC and i'm having major electrical problems.

 

First off is my taillights. They work whenever they feel like it and my passenger side light is dim and when my brakes or left signal is applied the passenger side completely goes out. Also my reverse aren't working now either. Sometimes when it gets too cold or whenever they feel like it they cut out completely. Also randomly sometimes my right signal will stay solid and sometimes it will work and my wipers work on and off whenver they feel like it.

 

I'm so confused on what exactly this could be. maybe a bad ground? or maybe my command start is wired funky and is messing with my lights. I'm not sure but i need to fix it and don't know where to start.

 

So if someone could please help it'd be much appreciated.

 

 

Thanks

 

 

Tyler

 

Tyler,

 

First off, these trucks has a lot of problems with the printed circuit board tail light assemblies. If you remove your tail lights (two screws for each side accessible with the tail gate down) you will see that the bulbs snap into a circuit board assembly. If these look or smell burnt, replace them. They are available from the aftermarket so your local auto parts store should be able to help.

 

Secondly, you need to check the grounds for all of the tail lights. This is located on the driver side frame rail behind the rear bumper. Make sure none of the tail light wiring from the lights to the harness breakout connector are shorted or open. Also make sure that if there is any trailer wiring or connectors back there to temporarly take them out to make sure that they aren't causing this concern. Seen a lot of the aftermarket trailer "T's" cause similar issues.

 

All in all it sounds for sure like a ground problem. Check the couple things I listed and then go from there.

[TSleid]

Alright so i took my taillights out and the circuit boards seem fine. I then looked at that ground on the frame rail and realized a bunch of wiring out in the open and some missing wires it seems and all. Unsure about what all the wires are for but did notice that there should be two ground wires on the frame rail ground bolt and only one wire is on there along with the head of a ripped out wire. So that could be it but i'm not to smart with wiring and unsure how i could fix it so i took quite a few pictures so you can get a better idea of what i'm talking about and maybe find a solution. This is all in the area of the frame rail behind the bumper. Any help and suggestions are appreciated.

 

Thanks

 

Tyler

 

 

[badass56]

none of that looks very good, i am not a gm tech but am a heavy equipment mechanic. what it looks liike you need to do is re wire the whole back of the truck, it might be a scary thought but a case of beer and a couple hours of your time should do the trick. DO NOT use those twist on wire conectors. they are not for automotive. go buy yourself a wiring kit and some wire from a auto store. just clean everything up, remove your grounds and clean all the rust off. this should cure most problems.

get some wire loom, electrical tape and get all the wires bunched together and clamp them up to the frame. this will help it from happening again..

 

good luck!

[TSleid]

none of that looks very good, i am not a gm tech but am a heavy equipment mechanic. what it looks liike you need to do is re wire the whole back of the truck, it might be a scary thought but a case of beer and a couple hours of your time should do the trick. DO NOT use those twist on wire conectors. they are not for automotive. go buy yourself a wiring kit and some wire from a auto store. just clean everything up, remove your grounds and clean all the rust off. this should cure most problems.

get some wire loom, electrical tape and get all the wires bunched together and clamp them up to the frame. this will help it from happening again..

 

good luck!

 

Yeah scary thought indeed lol. I'm an apprentice mechanic myself but wiring is really not my forte. Like there's a cut wire off on the plugs and i would have no idea where that goes too. But i guess i'll get a buddy to help as he knows more about wiring. But thanks for the help.

 

Also though another question. Would my wipers working whenever they want be involved with that? Like sometimes i get in and they work and then an hour later they don't. it's so confusiing.

[badass56]

none of that looks very good, i am not a gm tech but am a heavy equipment mechanic. what it looks liike you need to do is re wire the whole back of the truck, it might be a scary thought but a case of beer and a couple hours of your time should do the trick. DO NOT use those twist on wire conectors. they are not for automotive. go buy yourself a wiring kit and some wire from a auto store. just clean everything up, remove your grounds and clean all the rust off. this should cure most problems.

get some wire loom, electrical tape and get all the wires bunched together and clamp them up to the frame. this will help it from happening again..

 

good luck!

 

Yeah scary thought indeed lol. I'm an apprentice mechanic myself but wiring is really not my forte. Like there's a cut wire off on the plugs and i would have no idea where that goes too. But i guess i'll get a buddy to help as he knows more about wiring. But thanks for the help.

 

Also though another question. Would my wipers working whenever they want be involved with that? Like sometimes i get in and they work and then an hour later they don't. it's so confusiing.

 

 

 

 

invest in a test light, leave the one wire that your not sure about till the end, itle be easy to figure out then.

 

also sounds like your wiper issue is a diff problem, could be a bad wire connection for your wiper motor or wiper switch.

 

just deal with one thing at a time