96 C1500 Dome Light Issue

[Deranged]

1996 C1500, Dome and Cargo lamps have stopped working.

Steps I have tried:
1. checked all fuses, all show good
2. replaced bulb, no effect
3. checked all relays, all good

Odd thing is, the CTSY fuse 20A in the interior fuse panel is good, but if I remove the fuse and put it back in I get interior lamp on for about ten seconds and then I hear a small "tick" near the fuse panel and lights go out. During this 10 seconds the door ground switch will NOT kill the light.

I have tried the lamp selector switch in all 3 positions and get the same results in all 3.

Any idea what I am looking at here guys? Tried google for a good hour on top of self help under the hood stuff before coming to yall with what seems to be something simple and have had no luck.

Deranged

 

[Deranged]

Tell me if this makes sense:

ILLUMINATED ENTRY
When a door is opened, the Illuminated Entry System is activated. After the last door is closed, the Dome and Reading Lamps will remain illuminated for 20 seconds or until the Ignition Switch is turned on. Voltage is supplied to the module at all times through CTSY Fuse 3. The ground path is provided by CKT 150 to Ground G200. The module senses a ground signal from CKT 157 when a door is opened. The module then provides a ground path to CKT 156 which allows the lamps to light.

If I am plugging in the CTSY fuse it restarts the timer till off or ignition. With a door open it should remain on, however it does not. I have tested both driver and passenger doors and neither allow the light to remain on. I either got very unlucky and both door grounding switches went out simultaneously, or I could possibly have a bad lamp selector switch maybe? Gonna research how to test this next.

Deranged

 

[DieselCash]

Sounds to me like you need to go wire chasing. I bet you have a wire split and shorting out somewhere.

 

[Will L.]

I would be inclined to find that "tick". Sounds like a relay or self resetting circuit breaker under the dash that is overheating from a short. Otherwise a separate relay for the illuminated entry circuit you mentioned. Noises related to any electrical problem is usually a dead give away.

 

[Deranged]

I would be inclined to find that "tick". Sounds like a relay or self resetting circuit breaker under the dash that is overheating from a short. Otherwise a separate relay for the illuminated entry circuit you mentioned. Noises related to any electrical problem is usually a dead give away.

Wasn't aware of a relay under the dash.

Thanks, both of ya, that makes sense. I was thinking about when I last had the dash cover piece that just pops on and off removed and had trouble with that harness going to the headlight switch so left it connected. There are 2 ILLUM or COURTESY wires going into that harness and I think one could have been pulled loose from the harness or out all the way. Just being lazy and haven't removed the panel again.

Thanks for the replies guys, let ya know what I find.

Deranged

 

[Diesel Nut]

Look at the driver side pilllar behind the door. The wire for the dome runs up there. They are known for corroding out and then your dome lights quite working.