My GMC acadia has a short circuit and the engine keeps running after key has been removed from swicth. It also drains the battery from day to day. I have been in two dealers and they do not find the problem. I will really apprecciate if someone can provide a wiring diagram so I could troubleshoot the problem myself.

It could also have a Power Mode Mismatch . I would think the dealer tech would have found that if it were the problem . They over look the simple an look for bigger problems .
This vehicles power mode master (PMM) is the body control module (BCM). The ignition switch is a low current switch with multiple discrete ignition switch signals to the PMM for determination of the power mode. The PMM receives the ignition switch signals, and additionally a reference voltage signal from the BCM, through the ignition switch, and back to the BCM. There are redundancies within the PMM system that can allow operation of certain subsystems when there are faults in the ignition switch circuits. Other information such as serial data input from other modules and DTCs is also used to determine what power mode signals and information is transmitted by the PMM. The BCM logic uses all this information to identify the operators desired power mode and activate specific discrete signals, and serial data messages for the operation of many different subsystems as necessary. Other modules which have switched voltage inputs may operate in a default mode if the PMM serial data message does not match what the individual module can see from its own connections.

The PMM will activate relays and other direct outputs of the PMM as needed according to the calculated power mode. Several relays controlled by the BCM are switched ignition voltage outputs the are pass through circuits within the BCM directly from the ignition switch. If these circuits short to ground, the fuse to the ignition switch will open.

Some system functions may operate one time and not the next with a specific fault in the ignition switch circuits depending on the vehicle operating conditions when the fault occurred.

One of the first thing's would have been to check for DTC'S - diagnostic trouble code's in all the modules on the vehicle . It could also have a Power Mode Mismatch . I would think the dealer tech would have found that if it were the problem . They over look the simple an look for bigger problems . This vehicles power mode master (PMM) is the body control module (BCM). The ignition switch is a low current switch with multiple discrete ignition switch signals to the PMM for determination of the power mode. The PMM receives the ignition switch signals, and additionally a reference voltage signal from the BCM, through the ignition switch, and back to the BCM. There are redundancies within the PMM system that can allow operation of certain subsystems when there are faults in the ignition switch circuits. Other information such as serial data input from other modules and DTCs is also used to determine what power mode signals and information is transmitted by the PMM. The BCM logic uses all this information to identify the operators desired power mode and activate specific discrete signals, and serial data messages for the operation of many different subsystems as necessary. Other modules which have switched voltage inputs may operate in a default mode if the PMM serial data message does not match what the individual module can see from its own connections. The PMM will activate relays and other direct outputs of the PMM as needed according to the calculated power mode. Several relays controlled by the BCM are switched ignition voltage outputs the are pass through circuits within the BCM directly from the ignition switch. If these circuits short to ground, the fuse to the ignition switch will open. Some system functions may operate one time and not the next with a specific fault in the ignition switch circuits depending on the vehicle operating conditions when the fault occurred. One of the first thing's would have been to check for DTC'S - diagnostic trouble code's in all the modules on the vehicle .

Plus looking at ignition input's to the BCM ,to see what power mode it think's it's in . Plus looking at ignition input's to the BCM ,to see what power mode it think's it's in .