I have a 2009 Chevrolet Express Cutaway Chassis single rear wheel Cube van. It has the 4.8L. I have owned it about a month and it has always started fine, until this morning,

I got in the van, turned the key and the only action on the dash is the check engine light. Also no display on the radio except clock if hit the i button.

It does not crank most of the time I try, it but occasionally will crank, start, and die right away.

Day time running lights seem to be working. Heater blower works.

I have checked the fuses under the hood. All of the fuses under the hood that have power to them with the key on, are good. There are a number of fuses with no power to them. Mostly towards the passenger side of the van.

I swapped a the Start Run relay with another Identical relay. No Joy.

I removed some extra wiring that was on the battery. I found a Fleet tracking device connected to the BCM wiring and removed it, its lights seemed to indicate that power was happening at the BCM.

Also there is a Thump Thump sound coming from the stereo system randomly, but seems about every minute or so.

I suspect BCM but does anyone have any other Ideas or a good way to test the BCM.

I had one fail in my Suburban, but there were still various lights happening on the dash.

Thanks,

Rick

 

More updates.

Bought a wrecker BCM and an upgraded radio. (It was $35.00 and I figured it would not lock me out) Seems like its Aux plug is buggered. At least I will have CD now.

Now the truck starts and runs. No relearn procedure. Nothing for key.

Still have Service engine soon light but nothing else. No gauges no warning lights.

Seems like everything I can think to test works. Turn key off, truck shuts off, radio goes until I open the driver's door. Did not notice that before. It seemed like radio shut off with key.

Chimes are working properly no thumping from radio.

Instrument panel is completely dead.

Also, put original BCM back in and it behaves the same except the new radio does not work, it just says lock.

WTF?

 

Currently everything is working.

I checked every ground except one and they all looked good. The one I did not check was the ground used by the fuel pump and the pump was working so I figured it was fine.

I started removing the Instrument panel and when the trim released with a bang the panel came on. I took it all the way out and plugged the plug in and out a few times.

So, no good answers except I cleaned up a bunch of grime and extra BS wiring from previous owners.

I broke the trailer mode switch taking the trim off.

I hope this is not a sign of things to come.

I will try to get the radio unlocked and the used BCM programed for my truck.

I will also go back to the wrecker and try to get a few more parts from that van including the trailer mode switch, an under the seat fuse panel cover and heater vent covers that are missing from my dash.

I will update if there is anything to say.

 

Just wanted to add, I am almost wondering if the original radio failed in a way to make the BCM lose it's mind.

 

While your old BCM is plugged in which I suspect to be fine... did you plugged a scanner and look for any code ?
This would be my first step in finding the culprit instead of throwing parts.
Normally a BCM does not interfer with engine operation. It is there to control various accessory like the power windows, power mirrors, air conditioning, immobilizer system, central locking, etc.