Automatic Headlamps

Ok, Now on my 99 silverado i have the automatic headlighrs that turn on themselves after its dark, and its a 99 like I said so it doesnt have the cool little switch to turn them off like the new ones have, which would be nice to have, but the wiring is different, So does anyone happen to know how to disable the automatic headlights so I have to turn on the lights. Sometimes i like to drive with just the Parking lights on, but I can most of the time because its too dark out.. Thanx!!!

Short of rewiring you can push the dome light switch in and out three times and the headlights will go off temporarily.

Short of rewiring you can push the dome light switch in and out three times and the headlights will go off temporarily.

4 times. You have to push it 4 time within 6 seconds, you hear a chime, and the auto lights will stay off until the vehicle is restarted or the procedure is repeated. It's in the owner's manual.

sweet, When I bought my truck the owners manual wasn't there. Probibly a wise purchase, hehe, Thanks for the info!

Pushing the button doesn't work on a 99' You have to either live with the automatic headlights or bypass the Light sensor off of the BCM.

What I did was wire in a Micro switch with a 1.5 K Ohm 1/2 Watt Resistor across the pair of wires that go to the light sensor in the dash. When the Switch is closed the BCM still thinks it's daylight and leaves the lights off. When the switch is open the light sensor controls the lights.
Let me know if you want some more info and I'll see if I can dig up my notes.
Cheers
Evan

Yea saddly I found this out the other nite. please any info you can give me would be greatly appreciated

Bypass Automatic Headlights:


Basically you will need a pair of wire cutters and a 1.5K ohm 1/2 watt resistor that you can get at Radio Shack.

You may want to remove the neg. battery cable to assure you don't do any unwanted damage to the electrical system. This is not necessary, but a good precaution to take.

First locate the Body Control Module (BCM) which is under the dash, below the steering column. Laying on the floor, this should be visible without removing any dash panels. You should find a purple connector (C3). Unplug it.

Locate the white and gray wires (A4 and A6). I don't remember if white is A4 and gray is A6 or vice versa. It doesn't matter anyway.

What I did was tapped into A4 and A6 with my wire and switch so that it ran parallel as you can see in the Picture. Then hook it all back up together. To simulate a bright day engage your switch and have manual control over you headlights. To go back to automatic just simply flick your switch the other way.

Here is a simple diagram I drew up to help indicate what I did.

http://vvv.com/~evan/pimages/aheadwiring.jpg

Chuck, great information. Can you post that in your gallery so it can always be referenced? I like the idea of being able to override the lights BEFORE they turn on.

Thanks

This won't help with driving but you can start the truck with the emergency brake engaged and the lights won't come on until you release the brake.
sweet, When I bought my truck the owners manual wasn't there. Probibly a wise purchase, hehe, Thanks for the info!

Chuck, great information. Can you post that in your gallery so it can always be referenced? I like the idea of being able to override the lights BEFORE they turn on.

Thanks

http://files.automotiveforums.com/gallery/watermark.php?file=/500/217712aheadwiring.jpg

Ok It's in my gallery. Hope you can find it ok. :smile:

I just bypassed the sensor in mine completely. I like having total control of the lights. I wish I would have seen your diagram before i sired the reisitor in mine.

I just bypassed the sensor in mine completely. I like having total control of the lights. I wish I would have seen your diagram before i sired the reisitor in mine.

I thought about doing it that way but, wanted to see if i could do it with the switch just in case the wife wanted to use the truck. She's use to the Automatic Headlights now.

Thanks again for the info you passed along about this mod it gave me the idea for the switch...

:grinno:

ok well now i've found the wires, but i noticed that there are 2 gray wires, shaded a little differantly, but 2 gray wires, how do I know which ones which, Which im assuming ones A5 and ones A4

If you look at the Purple plug you'll see very hard to read writing that will indicate which one is which.
If you look at my diagram A4 and A5 are both gray. So it's the furthest gray wire from the white wire that you want to jumper.

Make Sense?

oo ok, mine had a bunch of electrical tape around it, so I didnt notice the writing, thank again for your help!!!!

Hey no sweat!