Re: Electrical Meltdown!!!
That has nothing to do with outside temps, you have an electrical problem. You mentioned that the last owner had the same thing happen, you have a short in a wire or component somewhere, you NEED to check each one of the wires in that harness and track down where the problem is. Something is drawing too much current for the wiring, this could be a hard short or a long term problem that heats and heats until a failure. I have seen this many times and it won't go away, you will replace it and it will fail again and again you need to find out the source of the problem.
Start by putting a meter on the wire and find out the draw, something might jump out as way too high then you can follow that wire and find out what is causing the problem, this can be a long process but if you troubleshoot one at a time you will figure it out. Find someone that is a good 12V troubleshooter, I installed car stereos, alarms and car starters for a few years and I had a good side business helping mechanic friends track down electrical problems like this. Don't assume anyone that can turn a wrench knows how to find this problem.