How to Fix a Pesky Door Ajar Light

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Door Ajar

Finding the source of a warning light problem can be frustrating. But our members can save you time, money, and aggravation.

When it comes to any vehicle, there’s arguably nothing more annoying than a problem light that won’t go away, whether that be a check engine, traction control, or door ajar light. So when Chevrolet Forum member tcup1851 couldn’t figure out why the door ajar light wouldn’t go away in his Silverado pickup, he did the smart thing and posted a query in the forums.

“I have a 2003 Chevy Silverado 2500HD 4×4 with 116,000 miles. When I put the truck in gear the CID reads that the Left Rear Door Is Ajar. I cannot set the alarm, the interior lights stay on while I’m driving and the doors will not lock. This past weekend I took the door apart. When I unplugged the wires from the latch and put the truck in gear it still said that the door was ajar. I took the latch out and tried it and it said the same thing. I called all the auto parts stores in my area and nobody had the latch assembly. Is that something that I’m going to have to get from a dealership? If anyone out there would happen to know how to fix this problem or what is causing it, I would greatly appreciate it.”

Clearly, he isn’t the only one having the same problem. Several folks chime in, including TpnTx, who’s in the middle of trying to figure it out himself.

“There is is a part inside the door just above the latch mechanism. It was two connectors plugged into it with two wires each. I had a tech from a car alarm company look at it. He has all the diagnostic devices for the Chevy. Thought he fixed it but not so. He said it was loose connection. I have mine apart right now. I’ve jumped each of these connectors in all possible combinations and the left door ajar message still comes up. I initially thought this was a BCM issue but he said it wasn’t.”

Door Ajar

Ballpeen4321 has had the same problem as well, but he might just know exactly what’s causing it. And it doesn’t have anything to do with the door latch assembly.

“I replaced my entire door jam/lock assembly with one that works from another truck. Did not fix the problem. I talked to a Chevy service guy who said that the problem is in the computer module under the dash. He said they could fix it and it would be between $400 and $600 with the new computer module and re-programming.”

It’s the same journey that TpnTx has been going through. “Its called a Body Control Module and is notorious for going crazy,” he adds.

Sure enough, MasterBlaster confirms that the BCM is the culprit after going through the same experience with his 2003 Suburban. On the bright side, his hours of research give us an incredibly helpful (and money saving) response.

“You can get a new BCM from rockauto.com (I am not affiliated with them) or many other online parts suppliers – it’s about $160. You do NOT need a dealer to “program” the BCM. The BCM’s job is to learn the passkey (anti theft / security) function from the ignition. Regardless if the the BCM is new or used from a yard it can be re-learned yourself by following this procedure.

Replace BCM, connect battery and ensure its fully charged. Keep doors closed / do not open during this process.

1) Turn ignition to run position – then to crank BRIEFLY (do not start engine) then back to run position.

2) Observe security light on dash – after 10 minutes it should turn off.

Repeat this process after successfully completing 3 consecutive cycles of ignition switch, vehicle will learn the new component on the next ignition cycle, which is from OFF to CRANK then to RUN position. Engine should now start.

Alternate/OEM Part Number(s) for the BCM: 15116066, 15136225, 15136877, 15137393, 15137394, 15137395, 15137396, 15198116, 15257043, 15257044, 15257045, 15257046″

Body Control Module

Even better, he learned that you don’t necessarily have to replace the ECM to fix the door ajar problem. And he provides a helpful video on how to reset it.

“Just wanted to add I’ve read a few people resolved their issues just by following the reset/ learn feature without replacing the BCM. I guess you have nothing to lose to try and reset it first prior to buying a module.”

Just another stellar example of how helpful the fine folks in the forums can be. Got a frustrating problem with your ride? Head on over here and take a look at the subforum dedicated to your specific model. Chances are, there’s already a thread addressing it. And if not, post away!

Brett Foote is a longtime contributor to Internet Brands’ Auto sites, including Chevrolet Forum, Rennlist, and Ford Truck Enthusiasts.

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