Daytime Running Lights

[Gapper_ca]

my daytime running lights just stopped working. check the fuse and it is good. not sure what else to check. command start will kick the park lights on but not the daytime. if i just start it then no lights at all.

[MTTwister]

And to think I had to go out of my way to disable mine. smile.gif

[MikeC]

There is a switch in the parking brake system that disables running lights until the brake is released. This stops the lights from being on while trying to start the truck.

Maybe that switch is the source.

Mike

[HowieE]

Who uses a parking brake?

I will check later and give you a complete list of the components in the circuit. Got to go.

[Gapper_ca]

checked the parking brake out. as soon as i press it a bit the brake light comes on and the daytime light goes off on the dash. i figure that there must be a relay somewhere that actually send power to the lights??

thanks

[HowieE]

The parking brake switch grounds out the circuit that controlls the day time running lamp module. When the Emergency brake is on the DTRLs, the low beam of the head lights, will not light but the brake warning light on the dash will light through a diode in the circuit.
Depressing the E brake pedal should turn the DTRLs off and light the warning lamp on the dash.
I would still suggest you look at the brake switch again. In the released position the DTRLs should be on. If they are not I would pull up on the E brake pedal and have someone check the head lights as you do. This is a common problem that can be a result of ware in the E brake pedal mechanics or ware at the brake pedal switch. If you can effect the lights this way the brake light switch needs to be adjusted with respect to the released position of the E brake pedal arm so the switch makes with any depression of the E brake pedal and opens when the E brake pedal is released.

[96GMC6.5TDSubOwner]

Do you know what happens to vehicles when the driver never uses the parking brake, it just "goes away" because everything becomes seized. And when you finally use it, you guessed right, it will not disengage. Cost me a set of rear brake drums!

[HowieE]

I don't use the parking brake not because it has no usefull purpose but because it one of the few remaing things, in New Jersey, I can deside on by myself and not get arrested for. So far our politicans have not yet figured out how to fine me for not using a parking brake and I will just do my thing till they do.

[jlog]

one experience of setting the parking brake during a chinook in Calgary Alberta and a drop over night to -40F. caused me to stop using the parking brake ever. had to be towed to a gagage and thawed out before the brakes would release.
john

[BBCB]

For me - it was the relay under the dash. About $30 from the dealer, but access to it was a big pain.

If I recall, this was a common issue when mine went out (2yrs ago). This forum had a lot of info on it - though a search doesn't seem to bring up the old threads.

If I could find my Shop Manuals, I'd give you the real part name. Irregardless, it mounts to the knee brace behind the dash to the right of your righ knee. Look for a large heat sink.

BBCB

[Gapper_ca]

thanks guys! i will check the e-brake again and then the relay. think that it is that as there is power to the parklights from the command start and e-brake does kick out the drl and set the e-brake light on dash.

[jspringator]

I use the e-brake every morning so the battery doesn't have to power the glows AND the headlights at the same time. I leave it on until I back out of my driveway, and release it before driving off. This makes the self adjustment feature on the rear brake work better. I don't leave the brake on all night.

[guns]

Its called a "Daytime Running Lamps Module" and is located Under the lefthand side of the instrument panel taped on the IP harness. There is also a "Daytime Running Lamps Relay" that is located lefthand side under IP. should be right above the "Hazard Flasher"

[Gapper_ca]

Ah well got it fixed now. what a job , it was the DIODE that is what gm calls it that was wonky. replaced it and all is well now.
thank you all for the info.