Reader Question: Balky Body Control Module?

Print Friendly, PDF & Email

Here’s the latest reader question, along with my reply!

Mark asks: Quick truck question. Just curious whether you have familiarity with this at the ready. I have a 2004 Sierra SLE, 2WD. My DDM (Driver Door Module) quit working on Sunday suddenly and w/o warning. No locks, no windows, no mirror control.The passenger side works perfectly. The keyless remote works, except that the driver door does not unlock/lock. I checked the instrument panel fuse, it was good. Any ideas? I’m getting ready to post in a GM Trucks forum. I don’t know whether you know that series of truck well or not. Thought I’d ask you quickly. Hoping it’s not the DDM but I’m guessing that it is. Not sure what else it could be, but typically when those go it’s intermittent with portions of the controls working/not-working, not a sudden crapping out.  At least that’s been my experience.

My reply: I ran this by my friend the professional mechanic; he agrees with your guess because everything isn’t working – which suggests the DDM rather than a particular component. Also given the age of the truck. That said, trucks much older – without body control modules – often go much longer without such problems, because their systems are discrete and simpler; just wires and connections – no “brain” to go senile!

If you can find a known good used DDM, you could try swapping it in to see whether it fixes the issue – before buying a new DDM.

Keep us posted!

. . .

Got a question about cars, Libertarian politics – or anything else? Click on the “ask Eric” link and send ’em in!

If you like what you’ve found here please consider supporting EPautos. 

We depend on you to keep the wheels turning! 

Our donate button is here.

 If you prefer not to use PayPal, our mailing address is:

721 Hummingbird Lane SE
Copper Hill, VA 24079

PS: Get an EPautos magnet or sticker or coaster in return for a $20 or more one-time donation or a $10 or more monthly recurring donation. (Please be sure to tell us you want a magnet or sticker or coaster – and also, provide an address, so we know where to mail the thing!)

If you’d like an ear tag – custom made! – just ask and it will be delivered.  

My latest eBook is also available for your favorite price – free! Click here.  If that fails, email me at and I will send you a copy directly!

Share Button


  1. One thing you might check which causes all sorts of electronic mayhem is a small ground wire that attaches to the body right under the drivers seat. They get corroded and things quit. It won’t hurt to take it off, replace the connector, clean the metal and bolt and screw it up tight again, and maybe a dollop of gasket maker around it.


Please enter your comment!
Please enter your name here