Does anybody have a pin out diagram or Schematic for the switch. I am most interested in the Dome over ride.
2002 Envoy headlight switch
- Thread starter Team Dougherty
- Start date
Schematics are in the manuals you can download from this thread: http://gmtnation.com/f23/need-service-manuals-get-them-here-371/
But you may be surprised to find out that the Dome Override is a mere momentary pushbutton that grounds a purple wire on the BCM called "LMP DEFEAT". The function is handled electronically by the BCM.
But you may be surprised to find out that the Dome Override is a mere momentary pushbutton that grounds a purple wire on the BCM called "LMP DEFEAT". The function is handled electronically by the BCM.
the roadie said:
That is the info I was looking for. I looked at those diagrams but could not find what I was looking for. Also, I had the switch assembly apart. It is not a momentary switch. it a click on and click off. and it is a double pole switch.
Learn something every day. Didn't know it was a double action switch. I thought the BCM had the memory function. Thx.
So. If I build a circuit that will ground that purple wire 4 times within 6 seconds when the ignition is turned on I can disable my DRL's and still maintain the perimeter lighting?
Does doing that manually do what you want? I didn't know 2002 had that function, but again, it's a bad day I can't learn new stuff about this platform.
the roadie said:
Yes if I press the dome over ride 4 times the drls are disabled until the ignition is turned off. The next time the ignition is turned on I have to press the dome over ride 4 times again. I am working, with help, on a circuit that will do this automatically every time the the ignition is turned on. I was just hoping to parallel the dome switch. Until I took it apart and found out it controls more that two pins on the back of the assembly and that is a double action switch. I forgot that's what they were called.
Team Dougherty said:
I like where you're going with your project.
Looking at the schematic, it looks momentary. Wish I had an 02 here to test.
With the headlamp switch unplugged, do pins J and M in the C1 connector have continuity when the over ride switch is pressed?
MAY03LT said:
Yes, there is continuity when you push once and it stays connected until you push it again.
I confirmed this morning that the switch is double action. I used two needles to measure the voltage between the purple M and the Black C1. It is 12 volts all the time. when you short C1 and M it draws 12.25 milliamps and you only have to short the wire twice and you get the familiar beep beep and the drls in fact go off. Short them twice again and they are back on.
So off to my electronics expert to design a circuit that will short C1 and M twice upon start up and my DRLs will be disabled and still maintain my perimeter lighting. :wootwoot:
So off to my electronics expert to design a circuit that will short C1 and M twice upon start up and my DRLs will be disabled and still maintain my perimeter lighting. :wootwoot:
My electronics guy is working on a circuit to disable the DRLs. His plan is to make it a three wire hookup. one to the purple wire, one to the black wire, essentially in parallel to the push button, and one to a switched 12 volt source. When I start the car there will be a 1/2 second delay then a pulse, to connect the purple and black wire, another half second then a pulse. this will disable the DRLs and the auto on headlights and maintain the perimeter lighting. :wootwoot: Since the DRLs do not come on until in Reverse or Drive this should work great for the guys who want to use HIDs.
This can be hook up behind the light switch or at the BCM since the purple wire and a switched 12v source can be found there as well.
My guess is this should work in any GM vehicle that has a dome over ride that disables the DRLs also.
This can be hook up behind the light switch or at the BCM since the purple wire and a switched 12v source can be found there as well.
My guess is this should work in any GM vehicle that has a dome over ride that disables the DRLs also.