Hello! I have a 2001 GMC Jimmy 4 door 4x4 4.6l, low miles. I love it and the thing is awesome.

I've just spent quite a bit of time researching my problem here and read through threads where people are asking things to diagnose, from a faulty intake manifold gasket to checking the alternator, and of course faulty switches and everything in-between.

So I apologize if I'm asking something that's been discussed over the last decade and solved, but I haven't really located a thread or resource that's been helpful to my situation.

That out of the way, my issues are these:

When I open any of the doors, the interior lights don't come on. So I use the override, or button on the dash to turn them on and off, which isn't a traditional way of operation and not convenient in any way. Since you can't even see the button in the darkness.

Also, whenever I open my back liftgate glass, the light also doesn't come on, which would be a HUGE help when loading/unloading back there. Possibly related to any of the doors not triggering the interior lights.

I've replaced all bulbs and the wiring seems intact. Although this vehicle is in incredible condition, I'm not the first owner, so I don't know the history of little things like this, and I don't know what the default protocol was for opening the doors/liftgate, lights coming on, then closing the doors, and when and how long the lights stay on and dim when closed. The electrical and wiring with cars are complex because the problem could be anywhere along any, usually very hidden, path.

I've owned an older Blazer before, many years ago, but not nearly as nice as this Jimmy. I just towed boats with the Blazer. This Jimmy is just an amazing vehicle that is in such great shape and a pleasure to own. I'd love to settle little problems like this with it.

Thanks,
Michael

 

4.3*L, unless you have a special little number under the hood.
Checked your door switches? the BCM controls the lights and the power feeds for them run through the light switch on the left hand side of the dash to my memory, somebody should have more information than this but start with if the truck even knows you opened the door. the lights should come on with the handle being pulled. not just door open too, they are commanded to stay with any vehicle door open.

 

Well, here's the way I like to make a bad situation worse: I went to check the "switch" which appeared to be nothing more than a protruding nub of plastic popped in below the fuses by the driver's side left knee. I thought " there's no way that could be passed off like a switch." Wrong. I popped it off and indeed it's what triggers the driver's door is opened or closed. And now it's not going back in so easily.

So before I make matters worse, is there another area I should inspect? You said that just pulling the handle should set off the interior lights, which it wasn't doing. Same with popping the rear glass. Or any door. Is there a main switch I should be looking for? Perhaps a blown fuse? (I kind of count it, but I don't want to rule anything out at his point.)

Thank you for your help and time with this matter. I sincerely appreciate it.

Oh, and thanks for the reminder, 4.3L, not 4.6. I haven't owned this all that long, and I wasn't thinking, clearly.

 

Well, that switch is broken, so no, its not going back in easily, assuming the body of the switch fell into the dashboard, going to have to retrieve that..
Check fuses absolutely, and if no yield then check your BCM wiring as it may not be outputting power to the system on switched command, i dont have a wiring diagram handy but one has been passed around several times, i'll try and locate it.

 

deleted, wrong section of the wiring diagram.