A while back I posted that my interior lights, all of a sudden, wouldn't shut off. Searching the threads, I saw a number of members mentioning a "door handle switch" as being a possible culprit if nothing else was wrong. After doing some research, I found that the switch in question is actually part of the door latch, not the handle.

Reasoning that the driver's door is the one that gets the most use, and since I couldn't find anything else wrong, I removed the left front door panel in order to check that switch (fig.1). I thought if I pulled the plug with the orange & black wires and the lights went out, that would be the culprit.

Figure 1


I got as far as being able to see the plug with the orange & black wires. It's the topmost plug on the latch, but that's as far as I got because it's so tight in there that unhooking the locking tab on the plug is impossible (fig.2). So I'm at an impasse and very unsure on how to proceed. Obviously I need to remove that latch in order to get access to the plugs, but I don't want to get myself in a jam for lack of knowledge. I have a new replacement latch. What I need is some advice or directions from someone who's done this R&R job before on how to proceed.

If you can help, PLEASE chime in. Thanks.

Figure 2

 

I once replaced my driver side door latch. Getting those electrical and mechanical connectors off is a bear! I had quite a few cuts on my hands after that job. Sadly, it turned out the latch was fine and instead it was an almost broken wire in the wiring harness to the door located in boot in the door jamb. Argh!

What I remember is that it was tough to get the wires connected due to lack of slack in the wiring harness. I had to be smart about the order I took them off and put them back on.

Do you have wiring diagrams for your diagnosis? I went on a wild goose chase due to forgetting that the door panel was necessary to depress the door jamb switch and forgetting to reinstall a plug to a security module on the inside of the bottom dash panel.

If you need wiring diagrams, I have a 99 service manual and have scanned several pages and could scan more for you if needed.

You might look at my build thread or posts by me to see if I included any useful info in them.

BTW, after replacing the the door latch, I just left it and now have a working used extra one. LOL

 

Thanks for the reply. And the offer.

I do have wiring schematics, but not the shop manual. After studying that door latch installation for a while, I figured the latch and handle must be installed at the factory before the window track, and I wasn't about to mess with that. So, instead of fighting with it, I bought a connector disconnect tool (Lisle 13120) pictured below. I used the hook end of the tool to unlock and pull off the connectors .... And with them all disconnected, my dome lights remained on.

I was able to get a couple very small alligator clips on the org/blk socket terminals and, using a test light while working the outside handle I found that the switch is working just fine - its On with handle lifted. Off when at rest. So that isn't the problem and I'm going to button the door back up.

However, yesterday I noticed that my 'dome override' switch is broken internally. Pushing it does nothing at all. No movement nor click. It just sits there in the same position no matter how many times it gets pushed. So I found a listing on eBay for a new genuine GM headlight switch (1 only) for a whopping 75 bucks! So I ordered it, and that's going to be the next thing I try. Whether that override circuit affects the lights-on-all-the-time problem remains to be seen.

PS The replacement door latch I bought wasn't correct anyway. It had only two pins in the one socket that takes a 4-wire plug, so I sent it back. That 4-wire circuit is probably unique to the LT trim but I didn't bother to research it.

In your shop manual, is there a step-by-step diagnosis for the interior lights?

 

I'll take a look at my manual for the troubleshooting on that. If you don't hear from me in a day or so, reply again here or DM me.

 

I've attached what I found in my 99 Service Manual. I hope it helps.