I've been running hijack and have been checking the temp pretty regularly while it's in the car and I've never seen it over 117F.

And, if it helps: I can't verify anything about how the wiring was done as I paid Best Buy to do it a little over a year ago (and it's run fine between then and now). Are the wires you're referring to labelled such that a sub-novice electrician like me could tell what he was looking at ?