Dome Light Mystery - Solved 8/17

[mx71]

Ok, I've been working on this all week and it's driving me crazy. I was missing the door jamb switch on the driver's side to get the dome light working when opening the door. It's on order. It works sporadically when just turning it on manually by shorting the red->black wire to the door's ground screw. I do have a new dome light coming to rule that problem out. Still can't get it to work, although when I did have a working switch for the driver's side it did work momentarily and so did the passenger side, but not any more. I did my best to locate any shorts without ripping out headliners and carpet and going through every inch of wire. Any ideas? I know it's a stupid problem to chase down, but it's one of the last mysteries left on this truck other than the tach not working.

[datzenmike]

It's not a short, that would blow the fuse. The lamp has power to it at all times like the brake lights, horn, clock... and the door switch simply grounds it to turn it on. Try repeatedly working the switch, on off on off on off, (possibly several dozen times) they get rusty and don't make good ground contact.

[mx71]

Well, I've disconnected the switch altogether and grounded the wire on a known good ground and it still rarely works.

[datzenmike]

Then the bulb or the clips holding it are corroded or loose. Try new bulb

[mx71]

Well the light works when manually turning it on, and it is a new bulb. I have a new fixture coming in case that's the culprit.

[datzenmike]

The manual is just a ground to the lamp case. The problem is the rusty door switches.

[mx71]

Scooby doo! Found the problem! Faulty room lamp timer. It would work when tapped, so I took it apart and cleaned it with 99% alcohol, but unfortunately that wasn't the issue. I ended up just bypassing that little bitch. I just have to remember to be mindful of leaving the door open.

[mx71]

For those that may have this issue in the future...the room lamp timer is the little box under the passenger seat. I hooked the ground (black) in the harness to the seat rail ground, and hooked the brown wire in the harness (which goes to the light itself) both to the Red/Black and the Black/Red, which connected the door switches to the lamp.