GM Repair Questions? Ask a Mechanic for Answers ASAP
Hello I iwll help you with your question,
Do you have DRLs on this truck?
If you do the light blue is the headlamp signal to the headlamp control modul and you will have to repair the break.
Here is the switch/control circuit
If you follow your yelow wire at "C" you will see that it goes to the DRL relay and that is why you see power there but do not have headlamps. The relay needs to switch to the other position at the command of the light blue wire from the control module.
Is the light blue wire broken right at the switch connector?
Ok, are DRL's the same as parking lamps? If so, yes I have them and they work. Where is the DRL relay? The wire is broken at the back of the plug for the headlamp dimmer. How do you take off this plug so I can fix it. Do I need to take off the steering wheel etc...or is that just if I need to replace the entire switch?
No the DRLs come on when the vehicle is in drive during the day with the park brake off,
There are several configurations of this so I have to know exactly what you have,
You can have the base package without DRLs and it may have Quad or dual headlights. Let me know whaich of these fit your truck.
You can have DRLs that come on during the day with the headlight turned off. They activate when the park brake is off and the transmission is in drive.
You can have the mac daddy package that has DRLs and automatic lights that turn on when it gets dark.
Let me know as there are four different wiring diagrams and this is hard enough.
The parking/marker/running/tail lights are seperate from the headlamps.
The headlamp switch is on the instrument panel so you are asking about the dimmer switch on the multifunction switch on the steering column and I read that this is where the broken blue wire is?
Let me know the answer to ALL these questions please
I am not even sure if the plugs come out of the multifunction swicth but it looks like they should. I ahve composite headlights. I will attach a copy of this vehicles window sticker. It doesn't say anything about daytime running lights. Does this help?
No it really dosent help, I would need the RPO sticker in the glove compartment to tell that way.
Anyway, the blue wire is burnt/broken at the multifunction switch?
You should replace the switch as it is not repairable at the harness to switch connection and you don't know how much damage is done inside the switch
The column has to come apart to replace the switch and I need to know tilt or fixed column?
Does the headlight switch (#7) have a small LED and a position where you can select auto?
Ok,, lite blue wire is definitely the problem. I connected a jumper to the plug and everything works fine. I just need to know how to take out the plug. It doesn't look easy. Do I need to remove the switch?
As shown in the diagram the entire switch needs to be replaced. Do you have a tilt or fixed column?
If you have never done this I suggest that you have it done but here are the directions, look them over and let me know what questions you may have
Notice: Refer to Fastener Notice in Service Precautions.