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Ask GM Tech (Cam) Your Own Question
GM Tech (Cam)
GM Tech (Cam), Chevy Technician
Category: Chevy
Satisfied Customers: 29534
Experience:  GM Grand Master Technician 2007. 14 years experience.
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Cam, my name is ***** *****. I'm having issues with my 2002

Customer Question

HI Cam, my name is ***** *****. I'm having issues with my 2002 Suburban, suspecting bad BCM.
JA: Thanks. Can you give me any more details about your issue?
Customer: Yes. First, Door Ajar light never comes on when any of the 4 doors open. Cargo Door Ajar message does come on. Also do not get chime when drivers door open and key in ignition. Dome ligths do not go out unless I push Dome Override, even when driving and all doors are shut And the big problem, if I lock the Suburban, the alarm will go off randomly.
JA: OK got it. Last thing — Chevy Mechanics generally expect a deposit of about $18 to help with your type of question (you only pay if satisfied). Now I'm going to take you to a page to place a secure deposit with JustAnswer. Don't worry, this chat is saved. After that, we will finish helping you.
Submitted: 1 year ago.
Category: Chevy
Customer: replied 1 year ago.
One more thing. Auto door locks do not engage reliably at 15 or 20 mph, they will usually eventually lock. And drivers door will not stay locked while driving. Other 3 doors are locked. If I push Lock button, it locks and immediately unlocks. And once in a while all the door locks will cycle unlock/lock while driving. Battery tested good.
Customer: replied 1 year ago.
Expert:  GM Tech (Cam) replied 1 year ago.

Hi there, I am Cam.
Can I get your first name please?
I am not sure if you have used our service before or not. The experts here are third party contractors. Myself, I am a GM technician in a Gm dealership. I will be happy to help you. Please understand that my only compensation for the time spent helping you is by your rating of my service in a positive way. The more information you provide, the better the chances of getting your issue resolved. Also please reply if you have any followup questions.
So about your vehicle, what testing at the door switches have you done?

Customer: replied 1 year ago.
I have not done any testing at door switches. It is weird behavior, on one hand it acts like a door is always open because the dome lights stay on, the drivers door unlocks if you lock it with key in ignition, and radio turns off as soon as I turn key off. On the other hand, I never get a Door Ajar light, but I do get Cargo Door Open light.
Expert:  GM Tech (Cam) replied 1 year ago.

It does sound like the drivers door. Can you remove the cover on the fuse block on the left end of the dash, in there is a connector, usually 12 pins for the door. Unplug that and see if the issue goes away. If no then I would agree the BCM or wiring around there. If so then wiring issues inside the door or boot with wiring to the door.

The BCM is under the steering column under the trim. It is a programmed module so its not a simple remove and replace,

Customer: replied 1 year ago.
Ok, I will check the connector in the morning.
Expert:  GM Tech (Cam) replied 1 year ago.

Ok, sounds good.

Customer: replied 1 year ago.
There were 2 connectors, one with 12 wires, salmon colored, left side of block. Another with 10 wires, black, top. Unplugged both independently and dome lights stayed on with door open or closed. Disconnecting salmon colored connector disabled drivers door lock switch and window, but otherwise behavior was the same. Lights on, no Door Ajar light, etc.
Expert:  GM Tech (Cam) replied 1 year ago.

OK, I am not at my toolbox and I don't have my computer running. When I do return to my toolbox, I will look up the schematics again and get back to you.

Customer: replied 1 year ago.
Did you look it up? Does it sound like the BCM? Dealer wants to send it in to be rebuilt - $300 & 10 days wait. I will likely get one on eBay and take it in to get programmed if that is the diagnosis. Please let me know so I can get the process started. Or if there are any other tests, let me know that.
Expert:  GM Tech (Cam) replied 1 year ago.

Sorry, today turned insane, looking now.

Expert:  GM Tech (Cam) replied 1 year ago.

That is not the BCM. It has 3 connector. Check the diagram posted.

Customer: replied 1 year ago.
I know where & what the BCM is. I've done the one test you asked and reported back results. What else should I do?
Expert:  GM Tech (Cam) replied 1 year ago.

The wiring you reported back on does not match the Body Control Module (BCM) though, thats my concern.

On the surface it does sound exactly like a failing BCM.

Customer: replied 1 year ago.
Please re-read the thread, you are contradicting yourself. You asked me to unplug connectors from the fuse box. You have not asked me to do anyhing with the BCM.
Expert:  GM Tech (Cam) replied 1 year ago.

OK that was for the drivers door, I did want you to double check for chaffed wiring around the Body Control Module (BCM). Try a tap test, which is tapping sharply on the housing of the BCM. Check each connector for corrosion or water intrusion (possible leaking windshield, and I have seen a couple), and if that changes nothing and on corrosion found then I would try a BCM.

Customer: replied 1 year ago.
Ok, will do.
Expert:  GM Tech (Cam) replied 1 year ago.

Please bookmark this page so you can easily navigate back to it so we can continue the discussion. This is done by pressing (CTRL D on PC and CMD D on Mac). You can reply at any time for follow up information regarding this issue, even after you rate the site and I will reply.