Chevrolet Avalanche Module Location

Question:
Above the spare tire, driver side, putatively attached to a cross member of the frame, is a 4 x 6 x 3/8 thing. A bundle of thin wires 1 1/4 thick attatches to it via the largest connector I have seen on this fat chevy. This thing is no longer attached to anything other than the wiring bundle.

Answer:
See picture below. am trying to get an idea of what you are describing. Is this component just off center toward the drivers side, or all the way on the drivers side close to the fender? Could you send a picture?

This part is Just off centre, above the spare tire, if it were in place. Component can not be seen if spare is hung in properly. Photo would take me a few hours to send: I am doing fall chores Thanks Tim.

Does it look like this?

Exactly, when it left the factory floor, I think. The connector end: wire harness is more than an inch in diameter and the connector, itself, is 3 inch long - and the girth - about the size of 1/2 a man's fist.

That is the electronic suspension control module. That would not cause a check engine light. You would need to get the powertrain computer scanned for codes to see what is causing the check engine light. Most of the large parts store chains will do that for free,

Thanks for the intelligence!