View Full Version : 90 cherokee aux fan relay...

June 4th, 2006, 07:13
Where is it located under the hood. I checked Haynes manual but no clue.
Any help would be great.:thumbup:

June 4th, 2006, 08:33
its located beside the air box on the fender.

June 4th, 2006, 11:53
It's also a standard Bosch/Hella relay, so you should be able to get one just about anywhere. Ditto most of the rest of the relays you've got - I do love standard parts...


June 4th, 2006, 17:38
But which one though? I thought that I have seen two there.

June 4th, 2006, 18:45
Do you have OEM fog or driving lights?

I think I sorted this out with someone else via long-distance - the one that is only a few inches away from the front end is the one for the lighting, and the one about a foot or so back is for the fan. I'm fairly sure of this, since I've got four rigs that did not come with lighting, and they only have the one relay about a foot back.


June 5th, 2006, 06:46
Yep got fogs. Ill try to post a pic?

June 5th, 2006, 09:26
Pics are nice, diagnosing a lifetime skill. Pull the one you think it is and then check your fog lights - if they still work, it must be the fan relay. If they don't work, you got the fog liight relay, the other is the fan relay.

You can swap them to check and see if the fan will work - but its usually the control circuit (i.e. the coolant temp switch in this case ) that won't turn on the fan.

June 5th, 2006, 12:23
Cool Ill try it. At what temp should the fan come on?

June 5th, 2006, 12:37
my "hot" wire to the relay is not "hot" where is the relay suppose to be getting voltage from?

June 5th, 2006, 13:03
Which "hot" - the coil feed or the power feed? Tracing backwards from the fan motor (in my 1990 FSM - other RENIX years similar...)

Radiator Fan Motor - the black wire is the ground, and is secured to the driver's side fenderwell. The Red wire is power, and comes from the cooling fan relay contacts.

Cooling Fan Relay - The OTHER red wire (the one that doesn't go to the cooling fan motor) goes to splice 10/8, which is an 18AWG green wire coming off of the start relay binding post. CAUTION - there are several green wires - you want one of the ones that has a 20AWG orange companion. That narrows it down to two - the other goes to the ignition switch.

I do not have a listing for splice 10/8, but backtracing the wire should locate it for you.

The distribution is handled via fusible link wire - if the link is blown, the B+ Latch relay won't work either (which will kill a few other functions, but I don't recall which offhand.)


June 5th, 2006, 13:26
Well . . Where's your coolant temp sensor located? IN the radiator you could see 230 on the gauge before it kicks, in the thermostat neck (91 up) about 210, which is why Chryco changed the location. I think the sensor itself is rated at 197. With a 15 pound cap you have plenty of margin.

June 5th, 2006, 13:37
RENIX? There are three -

The one in the driver's side radiator tank is the Thermal Fan Switch
The one on the driver's side of the engine block is for the ECU
The one on the cylinder head (driver's side rear) is to drive the gage/light.

I've heard good reports of people using an HO thermostat housing and moving the gage sensor or the TFS there - which will slightly increase the accuracy of the reading (gage) or turn the fan on earlier (TFS.) Me being me, I'd prefer to relocate the TFS, since it would get hot quicker (the driver's side tank is the "cool side" of the radiator.)


June 5th, 2006, 17:03
hard wire it.
it takes like 2 minutes

June 5th, 2006, 18:05
hard wire it.
it takes like 2 minutesThe fan to the ignition key switch?