Electronics Problem

crewleader22 · September 9, 2008

Hello everybody!

I have a problem with some of the power options on my '03, and was wondering if anyone could help. I have an '03 Chevy crewcab with all the power options. A while back, my wife noticed that the seat heaters weren't working. I took it to the dealership only to find out that it was going to cost me somewhere around $350 to get it repaired. They said the heater module needed replacing. It really seemed that they way they came about this deduction was by trial and error. That didn't work...so lets try this one type method. I didn't want to pay for that if it wasn't the problem so since the heated seats weren't that big a deal to me, I opted not to go that route. But since then I have noticed a few other things happening that seemed out of the norm. Then the other day my daughter went to get in the back seat and opened the back door before I unlocked the doors with the key fob. I knew I had locked the truck when we got out before, so I started investigating.

The key fob will open all the doors if they are all locked, but will only lock the front two doors. Likewise with the manual door locks on the door panel. I thought, by chance, that if I performed the vehicle's door lock alteration feature, like the locking sequence when the truck is placed in drive, it might have an affect on the situation, but it did nothing. So now I am writing this post in hopes that someone might have seen this same problem, and might possibly have a solution.

This is what I know has happened to this point: First was the seat heater problem. Then I noticed that when key 1 was inserted into the ignition, the presets didn't always go back to where they had been previously set, and setting the A/C presets didn't always hold their memory. Now the rear door lock situation. I don't know how long this has been going on, like I stated, the only reason I noticed it this time was by accident.

Any help will be greatly appreciated.

thanks,

Mike

Lincoln30 · September 9, 2008

I think you have a BCM (body control module) problem.

minibike132 · September 9, 2008

There are 2 relays in the left fuse panel for the rear door locks. One for lock one for unlock. Swap them around and see if it changes anything.

crewleader22 · September 9, 2008

The two relays sounds like a possibility, but in case that doesn't do it, is the BCM only available at the dealership, or can it be purchased at a parts house?

minibike132 · September 9, 2008

The two relays sounds like a possibility, but in case that doesn't do it, is the BCM only available at the dealership, or can it be purchased at a parts house?

Yes it's only available at the dealer and will need to be programmed after installation. I would check voltages at the relays before considering throwing a bcm at it though, it's pretty pricey to be wrong about. If I've had this problem a hundred times I would say 95 are the relay 4 are wiring and 1 was a bcm.

Lincoln30 · September 10, 2008

The reason I think it's the BCM is all of the problems mentioned, not just the door locks.

It's not out of the realm of possibility since BCMs are known to have problems occasionally. My 99 has had the security light problem for many years but nothing else has gone wrong yet and my truck still starts everytime (probably the passlock override for the remote start???).