Manual fan switch off battery to inside of car

[lupo.ewc]

I want to run a switch from my fan to the inside of my car. The fan works when I connect both wires to the battery but some of the wiring is missing because an engine conversion.

Do I need a relay between the fan and battery or fuse or what?

 

[plugsandsparks]

ideally, the fan (assume) radiator fan here, is switched by a temp switch on the radiator, just in case you forget to do it manually. The supply will come off a fuse, then to the temp switch, then to radiator fan. If you want a manual over-ride, then a relay can be connected in parallel with the temp switch, operated by a switch on the dash, with a little light to let you know its on. Remember to make sure the fan is spinning in the right direction ..

 

[fall-apart-dave]

Absolutely a fuse in there. Relay, that depends on your switch and fan. I had an oil cooler fan on my old T25 camper that had a manual override. I could switch it on or off from the cab or let the thermostat do it. But if you omit the fuse, you are writing to satan and asking for trouble.