The switches make "requests" to turn the lights on. The lights are actually powered by the Body Control Module. It's attached to the bottom/front of the heater box above/behind your center console (depends which console you have) behind the dashboard.

 

Ok we will check this out tomorrow and I will say ya or na if this fixes it, thanks alot

 

Well I have it all tore apart, found the bcm and cleaned the contacts for the 3 pigtails that plug into it, that didn't do any good. Took all three switches out (2 door and tailgate) ohmed the switches out and they work as they should, had 12V running to the switches but I could unplug the purple cluster of wires from the bcm and the lights would go out in about 20 sec. then I could push the key in to start and remove key and lights would come back on and then go off about 20 sec. later but when purple was plugged back in the lights stayed on and didn't make any difference if you started it and removed the key, still stayed on, this is with the door and tailgate switches unplugged, I replaced the light switch this weekend so either that is a bad one or the bcm or maybe something else I am over looking. What do you think?

 

if it works fine with the purple unplugged then i'm goning to have to go with a damaged wire somewere from the cluster you may have to trace the the wires from the purple cluster and see if maybe one is damaged and causing a ground out condition.

 

Nothing I did last night worked but today going to work I gently released the over ride button and the lights didn't come on and they functioned perfectly all day. This is the same thing it did before but would go back to malfunctioning so I replaced the light switch thinking the over ride button was bad. But the real mind blower is that the lights work when I open the passenger door and the switch has no wiring run to it, also I held the door closed while pulling up on the handle to see if an internal switch was hooked up to the handle but the only way the lights would come on is to open the door, I couldn't find any other contact switches to the door.

 

On my 2000 four door the front two doors both have switches in the handle that activate lights. Back ones don't. Makes me tend to believe you have a bad switch in the passenger door if the lights don't turn on if you lift it. That handle switch is connected via 4 pin connector with 3 wires in it, orange, black, dark blue/white. BTW that orange wire is also connected to your left and right jamb switches and connects to the BCM thru the purple connector.

 

But do you have the door pin switches also? The drives side doesn't activate either when you lift the handle but it does have a wired pin switch that activates when the door is open. Why would the lights not work when the handle is lifted but work when the door is opened when the door pin switch is not wired? I am talking about the passenger door.

 

<scratching head> I dunno how that passenger door jamb switch turns the lights on if it's not connected. I was looking at the factory service manual schematics (I'm home now, don't have it in front of me) & I'll try to explain best I can what I was seeing. The drivers side jamb, passenger side jamb and passenger handle switch all have an orange wire that connect together and become one orange wire before going into BCM. Drivers handle has a different wire because of the security system. Ground that orange and your lights will come on and I assume it *stays* on if it stays grounded like an open door - jamb switch. I know if you leave a door open or the dome switch on there's a power saver mode that kills lights after 20 minutes. I didn't look to see what function the 3rd wire (dk blue/white) connected to, I do recall when you lift the door handle it connects the black ground to both the orange and the blue/white thru separate switches. That handle switch is a 3 multi-part switch. (like your ignition switch actually has 5 different switches in it). If the lights don't come on when you lift the handle either the switch is bad, the wire(s) are disconnected, or the black wire isn't grounded. I don't know where the handle connector is in the door but with the doors closed (this won't work with a jamb switch made) if you connect black (or ground) to orange in the harness coming from the truck your lights ought to come on. Check make sure the black is grounded with an ohmmeter or a test light? Oh and the schematic didn't specify 2 door or 4 door so your front doors are wired the same as mine. Looking at things the other way, if the BCM thinks you have a bum switch stuck on it may be ignoring the switches and not turning the lights on. Pull the brown connector out of the BCM... (there was a warning, ALWAYS pull the brown connector out first and connect it last when working on the BCM), pull the purple connector out. With the doors closed, take an ohmmeter and check between the orange wire and ground to see if it's grounded like a switch is stuck on or the orange wire is grounded by a wiring fault. All the suggestions I have anyhow.

 

On the 98+, the jam switches for the front doors do nothing. As you said RonJon, they are not even connected. The switches that control the lights were moved into the door in the latch itself. When the door unlatches, the lights come on. Why GM left the jam switch in there is beyond me.

I do not know if the handle switch was a trim level option or not. My old 2000 Bravada had this feature, but I know that my cousins 1999 Blazer LS did not.

 

I didn't see any option notations on the schematic so I assumed it was standard. Then again I know the factory manuals aren't perfect either.