Accessory mode turns itself on

We have a 2005 GMC Canyon, purchased used in February 2009. It has recently started turning itself on (accessory mode only) when the car is in park and ignition is off, keys out, etc. Any feature left in the “on” position (radio, wipers, etc) will randomly turn on and will then turn off when the key is put in the ignition. The alarm also randomly goes off, again needing the key in the ignition to turn it off.

We’ve had this in to the shop three times now, and the problem’s not fixed. First they replaced a sensor/switch in the driver side door jamb, then the body control module computer, then reprogrammed the computer.

Any ideas on the culprit? Thanks!

As always a search of Technical Service Bulletins must be conducted.What I would do to diagnosis this would perform a systematic test with certain circuits disconnected. Like disconnect the ignition switch and see if it happens,disconnect the BCM and seee if it happens disconnect the multifunction switch, perhaps disconnect parts of the harness,disconnect the radio narrow this down to see just what is affecting this situation.

Has anyone suggest a new ignition switch? There are two parts to the ignition, the lock cylinder and the electrical switch. If there is a fault in the electrical switch it could cause this.

As oldschool suggested, a TSB search may be in order.

It sounds as if someone is throwing expensive parts at this problem, hoping one of them will solve it. Is this a dealer shop or an independent?