Quote Originally Posted by yqtszhj View Post
I like that backup plan. How much would you say the AZ heat contributes to the higher temps causing melting under the hood.

I had this electronics instructor one time that was retired from the air force and he said that some of the materials made to deal with the heat and pressures of automobiles were comparable to military grade stuff. When I started having to do research for components for computers I found out how cooling dependant most things are.
I'd guess the higher temps just edge stuff closer to their failure point. On really hot days, the cooling fan flow feels much like a heat gun.

In my application, the controller will turn the fan on anytime the AC clutch kicks in. Every time I've checked that, it seems the fan is in high mode. These are "hard" starts when compared to engine cooling where the fan starts in low and switches to high at a certain temperature; that gives the high side a running/soft start as the fan is already turning. I think the current spikes from the hard starts might be the major factor in the fuse holder heat. I could disable the AC clutch input on the controller, but I do like how quickly it makes the AC blow cold before getting up to speed or before the engines warms up enough to kick the fan on.