I have a 2003 4.2l I6 LS Trailblazer with over 186K Miles. Whenever I engage the rear window defroster it shorts out my power windows and locks intermittently almost like a timer every few seconds it shorts out everything. I have gotten by just not using the rear defroster but I am about to do...

2002 envoy_I have a problem every time I turn my defrost on my truck starts chugging and the rpm's go crazy then stalls out but it only has this problem when the defroster gets turned on heat and AC work fine truck runs normal, could anyone tell me what might be the cause of this?