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Im trying to sort out the fan on my 86.5 as i believe its never actually worked. First thing..With the ignition on shouldn't there power to the fan itself? The fuse appears to be ok[position 29] but i cant get a voltage reading at the connector. Also ive seen a number of references to hot wire jumpering the fan at one of the appropriate switches. Any body have a photo they can share of this? Thanks!
Hello dredpyrt, on my 86.5, the auxiliary cooling fan does not come on until the coolant temperature in the radiator reaches 90 degrees Celsius, or until there is X amount of high side refrigerant pressure when the AC is on.
Fan relay is called the 'Auxiliary Sensor' in the wiring diagram. It is relay XVIII.
Check out this screen shot of part of the wiring diagram:
Relay XVIII is a commom '53.B' relay. Try swapping it with another 53.B.
Check out this screen shot of a CE panel diagram that I got from Alan:
Using that diagram, you can see which relays to swap.
Also, make a fused jumper wire. Remove relay XVIII from socket 18. Using the diagram on the relay itself, figure out which teminals in the socket are 30 and 87. Jump them, turn the ignition on. The fan should run. If not, troubleshoot why.
To troubleshoot the activation circuit, use the wiring diagram and trace through the ground circuit through wire 85 to the radiator thermal switch or the AC pressure switch.
If I remember correctly, the wiring for the AC pressure switch has a junction by the AC refrigerant receiver drier, at the passenger's side front of the engine compartment.
It looks like this:
Disconnect the two wires that come from the car wiring. Jump them. With the ignition on, the fan should run.
I haven't looked for the radiator switch yet. I will soon, as I have a 75 degree C switch to install.
Okay, multiple confessions from a fellow 86.5 guy:
First of all Seth is spot on as to the correct methodology to troubleshoot this issue!
Secondly, I took the lazy way out.
Stop and go traffic is pretty brutal on my black on black car in the summer. I had a couple of close calls and never quite found the sensor reliable on the aux fan and I don't run my AC.
Anyway, I wired mine with a in line set up, and a manual toggle switch in the cabin. Probably overkill, but I can run it anytime i wish.
.... unfortunately another example of the long slow departure from pristine stock on my car.
I know some people have wired it to come on whenever the AC is turned on, to improve AC performance. I've considered that, but have more important stuff to worry about, and at any rate, I suspect any lack in AC performance is due to other things not performing up to snuff...so I need to sort those out first.
I had a broken connector on my radiator temp switch at one point, so to get around that I jumpered it, so it would run all the time with ignition on. If everything else in the circuit is OK, that should turn on the fan.
Since the majority of the relays in this car are still original i went ahead and plugged in a new one,jumped the leads and viola it works. Still dont really trust the switches so i had a thought. Could i put a toggle switch [with the proper amp rating of course] in place of a jumper and control it manually?
Sounds good. Shouldn't need much of a large toggle switch. All you will be doing is switching the relay.
There are a couple of ways to skin this cat. Easiest is to run two 16 gauge wires through some opening in the dash/firewall and run them to the A/C refrigerant pressure switch at the receiver drier. Plug your wires into the connections in place of the refrigerant pressure switch. Connect the wires in the cabin to your toggle switch.
Other way involves tapping into wires at the CE panel. Too much effort and possible damage in my opinion.
The problem now is finding said opening in firewall/dash. I cant seem to find anything existing and dont want drill any holes or tear the whole car to bits. Thanks for the info.
The problem now is finding said opening in firewall/dash. I cant seem to find anything existing and dont want drill any holes or tear the whole car to bits. Thanks for the info.
There's a rubber plug with extra (need to punch out) holes in the rubber to the Right and above of the steering column, the Front wiring harness that feeds the Outside Temp sensor, ABS(if equipped) Brake Fluid level and HVAC fan and wiper motor runs through it. Oh and also Vacuum lines for HVAC.
You will need to lay upside down in the Left side foot well to find it, it comes out behind the Windshield wiper motor, if you fish from the inside you can pull a wire(s) through
Wish i had logged back on a little sooner. I ended up punching a hole through the firewall just below the booster and then running the wires across the cowl and down the right side of the engine bay. Made for some fairly long pair of wires but made mounting the switch to the pod easier as i didnt need to run them around or behind the console.
The cars up thru '86 used a temp switch on the refrigerant, '87-up used a pressure switch.
The temp switch doesn't work very well. Some folks have installed an under-hood relay that operates the clutch and the fan. This does two good things - it runs th fan anytime that the AC compressor is operating, and it greatly reduces the load on the under-sized relay inside the HVAC head unit.
Takes a single-pole, single-throw 30-Am relay (the standard "53" relay will work - you just need a matching mounting socket); a 30-Amp inline fuse and holder; a power diode; some 16-gage wire and some connectors. You use the AC clutch to operate the fan and clutch, and the diode to prevent the normal fan triggers (coolant temp, ATF temp and intake manifold temp) from operating the AC clutch.
07-02-2016, 03:42 PM
Troubleshooting a 86.5 auxiliary fan.
