How to wire a switch to the radiator fan of a 99 jeep cherokee

Question

How to wire a switch to the radiator fan of a 99 jeep cherokee

Answer 1

Pops, Why do we need to run a switch to run the fan? Is the factory system not working? Would it be easier to fix the factory system? Just trying to help.    TW  

Answer 2

You can wire in a switch, and using a relay will help. Basically the power to the fan needs to be controlled (thru the relay) by the switch and back to ground. It means running long wires thru the firewall to the dash switch and back again. If you find the existing relay, you can use the leads from that to control it, and therefore, the fan.

The thermo sensor on the '92 up does not act like a switch - it gives a variable voltage reading to the computer as a heat input. The computer decides when to switch on the fan. Using the A/C should force the fan on, too. Jumpering power directly to the fan will diagnose whether it's working right.

Answer 3

If you want it run to a toggle switch, wire in a relay. You don't want all that draw to be going into the cab and through a switch.  It will get better power directly from the battery through a relay.  The thermo switch is the best way, so you don't have to remember to turn it on.  However it is not required to have an electric fan at all. My 93 didnt come with one and has not over heated here in Oklahoma where it has been 105*..  

Answer 4

well its actually hooked up to a temp sensor that plugs into the thermostat but if its not working you can take the 2 wires coming from the fan and hook it up to a toggle switch inside the cab, its gonna be a pain in the you know what though, that fan comes on a lot, the 4.0 get hot....real hot and needs that fan!!! you will have to turn it on every time you see it reading 210 degrees. try to fix the temp sensor...get a maintenance. manual, it will help a lot.