RX fan wire up

twilightprotege · Post by **twilightprotege** » Thu Dec 10, 2009 9:00 pm

I'm just in the process of installing air cond in to my 87 RX and at the same time install radiator fans (2 of them)

i noticed on the drivers side of the radiator there is a plug which I assume is for the stocko air-cond fan.

the question is - does that plug not only turn on the a/c fan when required, but also turn the fan on when the coolant temp needs it as well?

steptoe · Post by **steptoe** » Thu Dec 10, 2009 11:39 pm

I have two of these screw in fan switches you call plug on the lower drivers side. One in the side is the temp switch for the driver side electric fan and is only a switch for the low side of a relay mounted under the little vacuum cannister at back of engine bay RHS strut tower. It does the heavy switching. Below the temp switch is another that fits on the engine side of the same tank. Mine is was disconnected but had wiring that went to air cond switch wiring on dash. I think whenever A/C was on rhs fan was on. I guess you can try customise or optimise it to suit yourself and climate

twilightprotege · Post by **twilightprotege** » Fri Dec 11, 2009 8:01 am

confused! (then again, i might be just needing more "wake-up" coffee). any chance of a picture or 2?

steptoe · Post by **steptoe** » Fri Dec 11, 2009 9:06 am

there is a water temp switch RW,BW in series with a pressure switch BY, BW.

There is another pressure switch LW, LR not in series with the first bits.

there is a thermo switch B, YW may not be in rad but on evaporator.

Don't forget to include FICD in equation.

Looks like fan is on all while AC button is pressed.

PIC of the two switches? send me a PM with email addy and I will try.

discopotato03 · Post by **discopotato03** » Fri Dec 11, 2009 9:33 am

When I still had the original engine and AC gear in my 86 RX the condenser fan would switch on without the AC on when it got hot in summer traffic .

I ended up removing all the AC hardware and fitting a Davies Craig bulb type fan switch so it would work when I wanted it to and not at the higher temp that the radiator sender wanted it to .

Personally I think an aged L , what else is there , doesn't have enough cooling capacity and IMO the fix is the std mechanical fan and at least one std if not something a little larger elec fan .

Also importantly if you use that bulb type Davies Craig switch I reckon its far better to mount it at the radiator end of the top hose , I could never make the hose seal properly at the thermostat housing end and leaks on the engine itself can be confusing .

Hope this helps cheers A .

twilightprotege · Post by **twilightprotege** » Fri Dec 11, 2009 10:55 am

pm sent to steptoe.

disco - i am lifted and the mech fan will no longer work without hitting, so i've got 2 x 10" fans.

but that's good to know the fan comes on when the engine wants it not only when the ac wants it - i'll hook one up directly to the plug, then one on relay (surely 2 fans on that plug will draw too much)

discopotato03 · Post by **discopotato03** » Fri Dec 11, 2009 7:19 pm

I think you'll find that the sender is only supposed to trip the fan relay not actually carry the motors full current .
From memory I wired my Davies Craig switch to control the fans relay but it was a while back .

You may want to think about fitting a new rad temp sensor because as I found with original twenty something year old gauge temp sensor was not giving the correct temp/signal voltage .

Cheers A .

YouTube · Post by **El_Freddo** » Fri Dec 11, 2009 10:31 pm

To get around what disco is saying about the sender carrying the load you can run this through an aftermarket relay to power the fans - the bigger the relay the better (for load carrying capacity). You'll probabily find that the fans will work harder and therefore better as the I think the factory setup drops the voltage a little to keep the noise of the fans down.

After I added the second fan to my EA setup I found it went harder and was louder when in operation than the factory unit. I had a switch to activate it when ever I went off road. My aim now is to have an on-off-on switch to operate the fan (fans when I get another), one on for auto when the subi needs it, off for creek crossings, and on for when I want them to be on.

Cheers

Bennie

twilightprotege · Post by **twilightprotege** » Sat Dec 12, 2009 6:24 pm

yeah was thinking that - old wiring and the usual "on the smaller side of things" factory wiring isnt always the best