This fuse blows!... and so does HF!

[dazza]

First and foremost I'll address the latter of my title...
STAY AWAY from Harbor Freight blade fuses! For the past few days I've been dealing with my electric fan blowing fuses. When I first noticed my over-temp I found my 30 amp fuse between my battery and my fan relay had blown. This happened a second time on the next drive.

The third time, which was the first HF fuse I put in didn't blow!... no, the metal stayed intact but the plastic casing completely melted off into my fuse holder!
Spending yesterday troubleshooting the reason for the fuse popping, I took the opportunity to test the HF fuses with others I had and every one of the HF fuses melted without blowing, including a lower amperage (20A)!

In reality, I'm not surprised, and maybe myself and the one reviewer on their site happen to get a bad batch, but seems to me that's a company just asking for trouble.

In the end, I'm still having an issue if anybody can drop a little insight. Basically, when my temp sensor reaches the correct limit, the fuse pops. If I turn the truck off, replace the fuse, and then put it in the on or acc position without starting, the fan kicks in normally. So only when the truck is running. Here's a quick schematic of that circuit.