Aloha, Need help diagnosing my 96 Blazer LT 4x4.

My interior Lights do not turn off when doors are closed. Digging through the forums, i read it could be multiple things. door jamb switches, fuses, short in the wire, and i remember reading something about the BCM.


Door Jamb Switches - I removed ALL door switches including the rear glass switch. lights stay on


Fuse - Definately not the fuse. changed fuse. lights stay on.


Questions:
-could an aftermarket alarm cause interior lights to not turn off?
-with fuse removed. dome/courtesy light may flicker once when passenger door is slammed shut, didnt notice a flicker when slamming driver or any other door shut. does this symptom lean towards a short?
-My passenger door handle is broken. Where it screws or bolts (didnt get a good look) in side the door is broken. when passenger door is pulled. Handle pulls out away from door about 1cm. door still opens and closes. Tugging on either driver or passenger door without opening the door before this problem started would turn on courtesy light for 30 seconds then turn off. are there any diagrams as to what it really looks like in my door? its pretty cramped in there.
-driver door does not unlock or lock electrically with my old clifford matrix alarm remote, and using the unlock/lock button on driver door. havnt investigated as to why. but my theory has something to do with door lock actuator. maybe this has something to do with my interior lights wont turn off?


BIG QUESTION


how exactly do i find a short without physically inspecting wires. i have a fluke multimeter but dont know how to properly use it as far as testing for resistance, or voltage, or whatever. Im honestly have no knowledge on looking for a short. a walkthrough would be really helpful.


any input please

 

any inpute would be nice. please and thank u

 

yes it's sounds quite possible it's a short. Specifically a short to power. To find a short is rather difficult to explain, especially to a novice. I'll try to find a post or 2 on that..

In the meantime, search the Youtube videos. I know there are lots of "How To" guides and DIY's

This one shows short to ground checking.... #aid=P9-_amjL6Uo

 

Fuse will only blow when it's a short to ground.....meaning a normally powered wire is touching ground. Yes I can tell you have no electrical experience, hence the difficulty explaining it to a novice. crash course is still too much to teach. So try to learn from the videos and online sites.

the fact it turned off after 30 seconds is because of the BCM which has a timer when you close the door or until an alarm is set. That is normal

Did the lighting issue happen around the same time?

 

i'll do more research in the meantime on electrical. this problem started happening just about a year ago, but i never took initiative to look into.


With my somewhat diag i provided. Do u think a short to power is more likely than a bad BCM that doesnt turn the light off after 30 seconds?


That is something i literally cannot pin point. Im always using my remote for keyless entry, hitting the arm/lock button on my clifford remote, and walking away assuming my door was locked. the locking issue could have happened well before my interior light issue.











THANKS FOR THE INPUT CUBA. i posted the thread a few days ago and was impatient and starting to loose hope

 

Let me make a suggestion.... My lights would not turn off. I checked the condition of the switch, even pulled the lighting control module out of the passenger floorboard. The problem was the gap between the driver's side door panel and the switch plunger! Used epoxy to secure a black spacer onto the door panel and it works perfectly!

 

Yes the BCM can be the issue but the last resort because it networks with all Modules (PCM, TCM, RKE, etc) and may have to be programmed (if replaced) to network with the other modules.

RKE (remote keyless entry) is a possible issue too. Here's why:

"The module or receivers signal comes from the door jamb switches which ground at G200 and G201. The module or receiver must have inputs that indicate that the ignition switch is OFF, the courtesy lamp switch is OFF and all the doors are closed. The module or receiver will then activate the interior lamps. The courtesy lamps will remain on, approximately 15 seconds after the door is closed. If the ignition switch is turned to either the RUN or CRANK position the courtesy lamps will turn off immediately.

When the driver uses the remote function actuator transmitter to unlock the doors, or presses the panic button, the module or receiver will keep the courtesy lamps on approximately 40 seconds . When the driver uses the remote function actuator transmitter to lock the doors, the module or receiver will keep the courtesy lamps on approximately 2 seconds . When the ignition switch is turned to either the RUN or CRANK position the courtesy lamps will turn off immediately."

I'm guessing with the lights being constantly on, that it now won't "arm" with the keypad, right? Try each of these steps in order to and pinpoint your issue:
Did you try Dome override switch? Did they go off? If no,
Try unplugging the Headlight switch.... Did they go off? If no,
Unplug the Remote Door Lock Receiver.....Did they go off....

we'll continue from there and I see some of the answers to the above questions. I posted a pic to show where some of the modules are...

 

my alarm does arm/turn on when using my clifford alarm keypad. with the exception to the driver door, all doors unlock when "unarm/unlock' is hit on keypad. and all doors lock when "arm/lock" is hit on clifford keypad. and of course. exception to drivers door which doesnt move AT ALL when using alarm keypad, or the passenger and driver side unlock/lock all doors electrical button. But with all this, the alarm DOES turn on. with alarm on, driver door unlocked, door can be opened, but alarm will sound. locking driver door manually with a key or the manual lock/unlock on the interior door near the handle does work


Dome override switch - Dont have one, closest thing to it is the instrument/cluster dimmer that dims the cluster when moving up or down. When dimmer is turned up farthest, interior lights are suppose to turn on and stay on indefinately until this same switch is turned off (is this right?). This is located directly next the head light switch which consists of 2 buttons. 1 button for side marker/turn indicator, and 1 for headlights.


I didnt have time this weekend to wrench on her or try ur troubleshooting steps you stated, being that it was a very busy easter weekend. but i will try sometime this week. maybe today maybe tomorow. god knows with my busy schedule. when i do find time i will try removing connection to the headlight and dimmer switch (if this seems like a logical next plan of action since i dont have a dome over ride). See where i go from there then try the door reciever. but i will keep you and whoever else is reading this updated. THANKS SO MUCH CUBA

 

This just sounds like lock actuator in Driver door is bad, and not working. Replacing actuator for this door will solve this issue

Yes you are correct...& ok, so no override switch on yours -good to know. Not all models were equipped with it.

Glad I could be of some assistance & looking forward to your updates!