Q: Battery dying after sitting in 2001 GMC Jimmy

Hi there. There may be a parasitic draw on the battery. This can be checked by inserting a digital multimeter set to ohms inline with the negative battery cable. Generally, the current draw should not exceed 50 milliamps one hour after the vehicle has been turned off (the computer(s) need to go to sleep). If there is a draw on the battery, the offending circuit will need to be determined. One way to do this is by pulling fuses out one by one and looking for a drop in current draw. Of course, if there are any aftermarket accessories such as a stereo, lighting, etc., these items should be checked first. Add-ons are often responsible for parasitic draw. A trained professional, such as one from YourMechanic, will be able to diagnose the electrical problem with your Jimmy.