[shreve1]

Ok guys I got an problem. I been screwing around with my dome lights I installed after I eliminated my map lights. Due to changing out my mirror. Which did not have map lights. I am trying to figure out what is the hot wire and which is the fade out wires. Hope you guys can help me out. I know one side of the switch is 12v hot. Trying to find the wire that is hot and fades out or go off when the car starts.

 

[Sly Bob]

Check out the footwell lighting threads to find the wire

 

[1 LIL NDN]

Somebody did a thread on the mirror wiring .I think it was 2qk but whoever it was had all the wires labled . Get a needle point probe tester and connect the ground to a good ground (unpainted screw or bolt) then sit in the car ,close the door and probe a wire and open the door .If the tester lights close the door to see if it fades out . If the probe lightdoesn't fade out , go to the next wire Until you find the right one . Try the gray wire first that sticks in my head . Good luck you should find it just takes time . This is the wire bundle in the overhead

 

[2KWK4U]

I somewhat agree w/ 1 LIL NDN, except on the needle point probe tester. I STRONGLY recommend doing all of your testing with a volt/ohm meter or multimeter. Modern cars (i.e. anything built from the mid 80's on) have computers. Sometimes these computers run 5V reference circuits. Some of these circuits don't have the capacity to light up a 12V bulb... and will treat that bulb like a short to ground in certain circumstances. The net result is you can fry your computer by probing the wrong wire.

But yes, you're looking for a grey wire that is a ground when the lights are ON and loses ground as the lights fade. (so opposite what 1 LIL NDN describes).

Otherwise, 1 LIL NDN is spot on!

 

[GODROD]

I somewhat agree w/ 1 LIL NDN, except on the needle point probe tester. I STRONGLY recommend doing all of your testing with a volt/ohm meter or multimeter. Modern cars (i.e. anything built from the mid 80's on) have computers. Sometimes these computers run 5V reference circuits. Some of these circuits don't have the capacity to light up a 12V bulb... and will treat that bulb like a short to ground in certain circumstances. The net result is you can fry your computer by probing the wrong wire.

But yes, you're looking for a grey wire that is a ground when the lights are ON and loses ground as the lights fade. (so opposite what 1 LIL NDN describes).

Otherwise, 1 LIL NDN is spot on!

Yep I have a pic in one thread that shows the Grey wire in the BCM. Let me see if I can find it for ya. If i remember correctly it was 3rd wire from the left on the top row of the BCM...Please stand by.

Actually 3rd "slot".

Sent from AutoGuide.com App

 

[vcliment89]

shreve1 did you find out how to do it? I finished my installation of the lights and mirror last week but I'm on the same boat as you now, Thought the door lights were 12v but instead is just a signal of 1-2v. Wonder how to get 12v now when the doors are open...

 

[TX08manualGXP]

That's why I try and take photo's of everything I do. My wife thinks I'm nuts but you never know when someone else can use it. I used to do the poor mans probe where I'd use an old brake light bulb and 2 wires before I got a multimeter. got one on sale at harborfrieght for $2.97 with super coupon. I've had it for about 2 years now and it's never let me down. good luck.

 

[TomatoSoup]

Most of these things (mirror light control and door light switches) are ACTIVE GROUND! You need to find a source of always-on 12V from somewhere (i.e. the BCM) then the wire(s) in the mirror/door get switched to ground when active, to give you a return path.

You are NOT looking for a signal that gets switched to 12V when active.

Picture something like this:

+-------- 12V
|
(your light)
|
+-------- Door wire

 

[vcliment89]

Thanks TomatoSoup, that pretty much change my "light wiring harness" I made for those lights. It is like this:

The idea was to run another 12v to the other input of the switch when the door is open

 

[shreve1]

I got the fade to work. But now I'm trying to figure out how to get they to stay on when the switch is flipped to the other side.

 

[TomatoSoup]

Wire the remaining pole of the switch to ground (based on your circuit above).