BCM question

[Carjunky]

Hello all! I have a 04 Yukon Denali that is starting to have some problems, and I'm wondering if it's the BCM. It started when I noticed that I had to be on top of the Yukon before the key fobs would work. Then the fobs stopped unlocking the Yukon, but would still lock it. Now the Memory seats will not remember any new settings, and when you hit the heated seat button, the lights on it flash, and the heated seats do not come on. Use to when I started the Yukon, the driver's mirror used to adjust all the way out no matter where I set it. It did stop doing that a couple of months ago. I also have a pretty large parasitic drain that I can not find. Sometimes the Yukon will sit for a week or so before it is driven, but after about 3-4 days, the battery will be almost dead. The battery sat outside the Yukon for 2 months while I did the cam and head work, and the battery never lost charge, so I know it's not the battery. I'm thinking the BCM might be going bad. I also can not get the blend doors for the rear HVAC to work either. I was hoping someone could help before I take it to a shop. TIA

 

[ReaperHWK]

Did you scan the BCM for codes yet? I’d start there.

 

[Joseph Garcia]

Welcome to the Forum from NH.

Lots of knowledgeable folks here who freely share their knowledge, experiences, and perspectives. Knowledge is power.

I hope that you will become a participating member in the Forum's discussions.

Pics of the truck, please.

As @ReaperHWK asked, what trouble codes are being identified by the truck's diagnostic system. If you don't already have one, or have access to one, I recommend that you get yourself a quality bi-directional scanner to add to your tool box. Then, you will be able to read ALL trouble codes, along with a brief explanation/pointer to the source of your issue. You will also be able to reset/delete trouble codes, after taking corrective action. You will literally save thousands of dollars in diagnostic and repair costs over the life of your truck, and you will most likely recoup the cost of the scanner within 1 year.

Without a quality bi-directional scanner, you will most likely go down the parts cannon hole if you attempt to repair yourself, or be fleeced by the dealer.

 

[Rocket Man]

I’d say it’s more likely your battery as opposed to your BCM. Batteries tend to go bad over time. BCM’s do not. All your symptoms point to a weak battery to me. Just because it sat with no draw on it for 2 months doesn’t mean anything either.