Thread: Help diagnose: courtesy lights always on *SOLVED*

I will try to keep this as brief as possible.

My issue: Interior lights stay on with all doors closed until the BCM times out. (10 or more minutes?)
I am lead to believe it's a bad door actuator not telling the BCM the door is closed. So, which one...? Using this wiring diagram:



and doing this:



I have determined that the 3 passenger doors all function as they should using "DK BLU" (bottom pin in this ^^^ picture). I have an open circuit when the door is shut, and I have continuity to ground when the door is open.
There are two other dark blue wires in this connector. One solid blue, one blue with white.
When I check the other dark blue wire, I have continuity all the time. (DS door open or DS door shut). Not shown in picture. Bottom row, 5th from left. Thinking this may be my DS door wire?
When I check the dark blue with white, I have no continuity. (DS door open or DS door shut). Top pin in picture. This one may go to the headlamp switch according to the diagram.
I am thinking my manual has the wire color combinations wrong or it's outdated for my car.

So, I guess what I'm asking is; Am I using the correct spot to check continuity for the drivers door actuator? Also, wouldn't the DIC show the door open if the actuator wasn't opening the circuit?

2000 GTP Sedan

i shouldn't,,,,,but i bet its the door switch is busted.

Originally Posted by Scottydoggs

i shouldn't,,,,,but i bet its the door switch is busted.

Shouldn't bet, or shouldn't help me?

help lol

after the lights time out, open the pass side door, then shut it, if the lights go out the driver side light button is bad.

They stay on.

But in this scenario, wouldn't they? The BCM still sees the drivers door as open. Even after you close the passenger door, it's still "waiting" for the drivers door to shut. Anytime you open any door, it resets that timer. Right?

Oh, and thanks for the help. Unless you're purposely sending me on the wrong course for your enjoyment! Lol.

nope not f ing with you for my entertainment lol

look for the switch in the door jam, and then for a bad wire.

my thinking with the pass side door is if you open and close it and the lights go right out, the driver side door is the problem.

Aren't the switches part of the door actuator?

I was doing as much as possible to diagnose without taking the panel off. That thing is old, and already missing a couple mounts.

not sure on the gp's its in one or the other side of the door jam, on the hinge side, or lock side.

id check the pass side door out, if the lights are on then off when the door is shut, id be looking at the d/s door for sure.

Looks like the LH front and LH rear are interchangeable. Maybe worth swapping to confirm function. Or dysfunction.

Wondering if anyone has a more current wiring diagram for my BCM?

Well, It's not the actuator. Pulled it out, and bench tested fine.

I'm thinking broken/chafed wire, or more likely the BCM.

Simple thing here.. Drivers door gets used a lot more than any other door. Pop panel, unplug and you have a 98%ish chance it's that one

I totally respect your experience Bill.

But here's the details.
1.) Problem is intermittent and completely random. Lights work as they should for weeks, then one day, will just decide to stay on!
2.) Switch/actuator tested fine while out of the car.
3.) At some point the other plug (controls door lock/unlock) had been tapped into. Whatever they installed has been removed, but the little inline wiretaps were left behind. <--- This is why I suspect the BCM. I have no history, but I wonder if whatever was installed, cooked something inside there.

If something were cooked, it wouldn't be intermittent. I'd aim to the driversdoor and or the wiring inside the boot to the door. Here's why.. is there always someone with you when it happens? Likely not.. so it's very likely the door.

This reminds me of when I was trying to diagnose a bad brake hose in a car. I asked my buddy to explain to me how to diag it. He simply said "I could..but it'll take longer than you swapping a new $12 line on and being done, trust me".

Give it a try..

Fair enough.

I guess I'm just chasing that "ah-ha" moment when I can prove something through diagnosis. For me personally, the proper diagnosis is just as important as the repair. Maybe because I'm a noob, I want to learn as much as possible.

Not at all. Diagnosis is most of the work in many repairs. However there are a few constants here that we should go right to and look at (aka diagnose).

Similar to how we wouldn't suggest the fifty steps it takes to diagnose a crank sensor when we see common issues.

Okay, just installed a new to me (junkyard) actuator in my existing lock/latch assembly. I pulled it from the left rear of a 4 door. Bench tested with dvom to confirm proper function. Got it all buttoned up and the problem persists. Next step... Testing the wires at the door disconnect connection?

Figure out which wires are the drivers door at the bcm connector you pictured. Test for continuity to the door.

See, this is part of my problem. I found, and can test the wire that signals the three passenger doors, but I can't isolate the wire that signals the drivers door. Latch open/latch closed, nothing changes at the BCM plug. I'm not calling that gospel though. I don't know enough about electrical to say that the drivers door works exactly the same as the passenger doors. It could signal in a different way. I'm stumped there.

So..... I thought I would take a less technical approach. What I've learned so far is, an "open" circuit = "closed" door. So, I should be able to disconnect the actuator, thereby opening the circuit and telling the BCM that the door is shut. So that's what I did. I pulled back the rubber boot thing in the door jamb, and disconnected that big plug. Didn't want to pull the door panel again. As expected, DIC shows the door as shut, no chime with key in ignition, typical closed door scenario.

Lights stay on.... Till the 10 minute(?) timeout. Same as before.

Is this a valid test? If not, what am I missing. Why am I wrong? I have all but ruled out an actuator unless someone can explain how that could still be the problem. Not trying to sound like a jerk. I legitimately want to learn.

FWIW, the problem has gone from intermittent to constant. Does this mean it could be the BCM? Maybe a headlight switch? I could grab a BCM and a headlight switch from the local pick a part for less than $40 if either of them are a remote possibility.

Also, I did inspect the wires at the bend when I had the boot pulled back. All looked factory fresh.

Any other things I can test or look at? Any suggestions?

Made a trip to the Pick-a-part today. Swapped some parts. Still no change. So here's what we know is NOT the problem;

Door actuator - Confirmed via DVOM and/or physically disconnected the switch to open the circuit and tell the module the door is shut. (For all doors)
Headlight switch - Swapped for a JY unit. Situation unchanged.
BCM - Swapped for a JY unit. Situation unchanged.
LED bulbs - To rule out as a cause, I swapped all LED bulbs back to standard incandescent ones.

The only other thing I can think that affects interior lighting is the ignition switch. Is it possible this is the cause?

this sounds like the problem im having with my interior lights always on, but when i shut my car off and lock it, they turn off but in far less than 10minutes (under a minute)