cuel said:
A 30 amp relay is cheap insurance against burnt up fan motors or switches
This brings up I question about my set up. I was running a Perma-Cool High Performance Electric Fan,
part # PRM-19115 (link). I had this wired up with a relay that was triggered via a switch in the car. All wires were 8 gauge high quality car audio power wire, and the fuse was a car audio fuse set up.
The fan burnt up on me after about 500 miles, I opened the can up to find that the wires inside were soldered to the brush housings and had come off and shorted out inside the motor. I replaced the internal wiring and soldered the same way as the "stock" wiring was.
This lasted about another 100-200 miles before the solder melted again.
Then I tried solid mounting the wire to the brush housings as to not let the wire come loose from the housing even if the solder came off, this lasted about 50 miles before the fuse popped, and this time the motor housing and wiring was too hot to touch. And when I opened the can this time the wires were still in place but the resin coating on the windings had failed from the heat and the windings shorted out.
So I got rid of that fan and I just got finished installing a Flex-a-lite Black Magic Electric Fan. I have it wired up the same way as the last fan, as the relay and wiring still seem to be working. The only difference this time is I have another fuse on the + wire right at the fan (the primary fuse is in-line before the relay)
I have yet to drive the car with this new fan. But what would cause the last fan to burn out like that. I don't want to ruin another ($$) nice fan. The relay is rated at 30 amps, the primary fuse is rated 30 amps, the new secondary fuse is rated at 25 amps.