Aux fan relay wiring.

I know this is about a newbile question as thier is but I'm a slow learner:doh: that isn't good with electrical. I really need to get my Aux fan hooked up so I quit worrying about overheating all the time. So is there somebody who could walk me through the wiring of it. I have the relay and switch wires etc just don't have the wiring guru brain. What goes where on the relay, which wire is the positive wire to the fan. I really appreciate the help. I've gotta get this done before the next run. The list never ends does it. Thanks for the help



Parakeet

Try this link:

http://www.lunghd.com/Tech_Articles/Cooling/Electric_Fan_Diagnosis.htm

I have this other link but my browser says it's out dated, maybe yours will get a different result.

Here: http://www.olypen.com/craigh/auxfan.htm

What year? It makes a difference...

And, are you trying to make it "always on," add an "Override ON" switch, or just make the wretched thing work in the first place?

5-90 said:

What year? It makes a difference...

And, are you trying to make it "always on," add an "Override ON" switch, or just make the wretched thing work in the first place?

Click to expand...

I'm sorry I didn't even think to let you guys in on that info. It's an 89 4.0L with a cooling system conversion. I want to put it on a switch so I can control when it is on or off. This summer I would overheat and have to run the heat at stoplights. I'm also running a 160* stat right now but it's cooled down enough that it doesn't warm up enough driving on the highway that my gas milage is enough to make me uke:. When I do wire the fan up I'm going to throw the a 195* stat back in it. I just don't know how it will fare the trail in 4lo with the 195* stat in it.


Parakeet

4wdParakeet said:

I'm sorry I didn't even think to let you guys in on that info. It's an 89 4.0L with a cooling system conversion. I want to put it on a switch so I can control when it is on or off. This summer I would overheat and have to run the heat at stoplights. I'm also running a 160* stat right now but it's cooled down enough that it doesn't warm up enough driving on the highway that my gas milage is enough to make me uke:. When I do wire the fan up I'm going to throw the a 195* stat back in it. I just don't know how it will fare the trail in 4lo with the 195* stat in it.


Parakeet

Click to expand...

That's easy. Take some 18/2 SJOOW cable (get it at your hardware store,) and tap into the leads off of the thermal fan switch in the driver's side radiator tank - it looks like a large brass bung with two wires sticking out of it. Run the other end of the 18/2 (18AWG, two lead) cable to a convenient point on the dash panel, and wire in a toggle switch. When the switch is ON, the system will think that the TFS is closed and the fan will run as long as they key is ON. With the toggle OFF, the fan will operate normally.

Running a 160* won't do much for you, but switching to a 180* is a good compromise on RENIX. You'll also want to look into adding some Redline Water Wetter to your cooling system - the stuff does make a difference! Make sure your system is flushed well, and use either distilled water or reverse osmosis-filtered water only to mix your coolant. That should be good for a drop of some five degrees in your operating tempeature - 205 or so down from 210-212...

I actually don't have a sensor on the radiator. That's why I have the relay and such.



Parakeet

Ah.

There's still a relay for the fan - it's on the driver's side fender liner. There has to be - none of the switches are big enough...

On the RENIX setup, the auxiliary fan is controlled with a separate circuit, and is engaged by either A) the relay is triggered by the thermal fan switch (which you have deleted, apparently,) or B) the A/C REQ signal from the HVAC controls. What you're doing is adding a third signal.

Also, you can replace the thermostat housing with a 1991-up housing, which has a 3/8" NPT hole drilled and tapped. You can then put a thermal switch in there, extend the OEM wiring to the switch that used to be in the radiator, and use that to make the fan automatic. I'd suggest probably a 205* ON and 190* OFF switch, or a bit lower - I think there is a Corvette part that works handily.