I cannot find the computer brain box for this vehicle. It has a 350 engine. It's not under the dash or behind the glove compartment area nor is it under the drivers seat. All these areas I am being told by the GMC dealership. Does anyone know where it could be?

Have you looked under the hood? GMC mounted the ECM between the engine and the battery on some models.

Normal location is under the driver's seat but it could be on the backside of the driver's door pillar.

Thanks but it wasn't there either.

Yes. It's not under the hood anywhere. Thanks.

Are you certain that we're talking about the Engine Control Module?
What are your symptoms? Why are you looking for the ECM?

The Electronic Control Module or what they call the computer box controls power to the fuel pump back at the tank. When we start having fuel problems we repaced the fuel pump, the filter, the relay, and the oil pressure switch. We were then told it was the brain. I use to be able to get the pump to come on and it would run all day, but as soon as you turn it off-that was it! It wouldn't crank for days! Now it won't come on at all-but the pump is still good because there's a way of testing it. Now if we can just find that ECM. What do you think Capt. Rich? By-the way this van does not have a crankchaft sensor.

Unless your's has been installed in either the left or right kick-panel, I would need to personally search the vehicle to find your ECM.