View Full Version : High speed fan wires on '94 - '95... HELP!

04-26-2003, 12:11 AM
Anyone know which of the three wires going to the BIG cooling fan on late model SC's is the ground? I need to test it and see ~~~ it's not spoolin' up...

About two months ago it started running hot and I discovered the 60amp fuse in the power dist. box had nearly vaporized (melted plastic and everything)... I did manage to stuff a new fuse in and it's worked for two months now but I never figured out why it popped in the first place.

Now the fuse is still good and has juice through both sides but, the fan is dead and shows no signs of recovering.

Anyway, I want to see if it spins with 12 volts jumped to it and, if it does, I suppose my computer is beginning to puke, right?

I don't freakin' know.

Well, I'll close with asking anyone who's successfully wired their HS fan through an alternate wiring route to please share the scoop...

I'm peggin' the temp gauge and it's only 80 degrees out here!

Thanks all,


04-26-2003, 12:25 AM
if there's a solid black one, thats probly it....(really not sure) i have an early model(1990). but i ran a in line toggle to the ircm, pin #17, and then another wire from the toggle to ground...but on the early models, u have to get the fan to kick low speed first then you can turn the high speed on....b/c the high pulls to many amps...hope this helps but i could be wrong....

04-26-2003, 01:58 AM
I found the solid black one after cleaning off 85K miles worth of grime and tested the fan. It spins on both high and low speed tabs and seem to be happy. So, I then turned the car on flicked the A/C to max (turns on the fan at any temp) and I tested for any juice from the harness into the fan.... zilch. No juice from either of the hot wires.

Now I'm wondering if it's the ircm (what the hell does that stand for, anyway?) and I'm curious to know if there's any way of testing it as a unit and/or what a new one costs...

Anybody been here before?

BTW, twindragons, I looked on the wiring diagram and found pin #17 going to the PCM... Was it different for '90 models or was there some logic in your use of #17?

If I'm thinking right (and I'm rarely ever thinking at all, let alone right) it sounds to me like you just wanted a way to flick your fan on and off when you wanted too, rather than letting the computer run the show, is that right?

Thanks for the help, bro!


04-26-2003, 03:03 AM
IRCM(intergrated relay control module) runs all the motor relays.. its the box behind the pass headlight...actually, i put a inline toggle(30 amp) and inline fuse(30) to pin #14.(low speed) if you want low speed to run, cut pin #14 and the fan should turn on...now with what i did, i can break the circut to pin 14 (turns low speed on) or i can reconnect the circut(turns low speed of) with the inline toggle. otherwise, i can turn on the low speed fan manually, or let the ircm do it...

pin #17 runs the high speed fan. from 89-93, we have 1 fan with 2 speeds and from 94 on, they used 2 fans...

find pin #14 in the ircm and cut it, but make sure you can splice it back togather(so don't cut it too low). this should turn the fan on, if it doesn't, then you have another prob...

04-26-2003, 05:36 PM
...I think the relay control module has puked and is not sending any signal to the fan... I think. The fan works when I hit it straight from the battery but, when I tested the wires that feed the fan, there's no juice at all...

Now, I'm assuming there's a relay between the 'ircm' and the fan motor which I should check first, before I spend a Franklin on a new black box...

Anyone know where the fan relay is located and how I should go about testing it?

Also, if the relay does seem fine and there's an obvious problem in the 'ircm' I wonder if anyone's just bypassed the 'ircm' alltogether and wired the fan to run constantly with ignition on...



04-26-2003, 11:40 PM
there is no relay between the ircm and the fan, the ircm IS the relay...if you want the fan to run all the time, cut pin #14 and leave it alone....the fan will come on whenever the key is in the run position...but be warned, this could cause slow starting b/c the fan starts to run when the key is turned...but alot of people have had no prob with doin this...

04-27-2003, 03:30 AM
I figured the relay thing out not long after posting and then immediately began feeling STUUUPID!

Thanks for your help on this, I've got it cornered to the ircm but am waiting on a couple of replies regarding bypassing the ircm alltogether. I'd rather drop a couple of bucks in some relays, fuses and wire and have it turn on at a cooler temp than the factory setting anyway...

Thanks again for all the info and I'll let 'ya know how it turns out!


04-27-2003, 01:51 PM
Look next to your battery. There are two fusible links there. One is for the fan. I've had it burn up on me before. Not sure what the color of it is. My 89 is orange and my 90 is black. If ones fried, chances are its the fan link.


Joisey Jim
04-28-2003, 01:28 PM
HJM - same thing happened to my 94, my fuse fried and even damaged the box. Unfortunately I also tested the fan and it was dead, so I guess the motor going bad caused an overload. When I installed the new motor I went back to the earlier model wiring system with a fuseable link and powered it off the main terminal on the side of the fuse box. Since then ok.

Duffy Floyd
04-28-2003, 07:31 PM
I assume the clutch for the AC compressor cycles yet the fan will not run? If the AC System lost its charge of freon to such an extent the clutch is locked out then the fan will not turn on regardless if you have the AC "on" or not.

Also to check the IRCM operation pull the electrical connector to the ECT sensor (the one on the intake manifold not by the Thermostat housing) . If the fan starts the problem is NOT the IRCM.

All suggestions based on the fuses and fusible links being good BTW.

05-01-2003, 10:57 PM
I corresponded with an SC God and he had me check both of those items. The fan wouldn't run when the A/C cycled and, after unplugging the ECT, the fan kicked on and worked normally!

So, he (God) recommended that I replace the ECT. I thought that was a good idea too and decided to drive to the Ford shop. Well, I had reconnected the ECT by now and I then had the check engine light glowing in the dash... Curious, I checked it out and it told me the ECT was out of range, hmmmmm.

Well, without any new parts I decided I'd risk running hot and drive to work the next morning then go get a new ECT...

Here's the freaky *****.

It's running fine now, no check engine lights for two days and the fan is again operating normally! Weird, huh?

I'm thinking the connector to the ECT was either loose or corroded. Either way, I'm gonna' keep on drivin' 'till it happens again...

Thanks again for all the help, guys! I nearly replaced the ircm and as it turns out (for now) I didn't need to!


05-02-2003, 08:16 PM
I replaced the ICRM. I think it cost me around 65-70 bucks last summer. I also replaced the coolent sensor. For about a hundred bucks I was back on the road with no hassle. The temp is never past the left side of the "R" And I live in Yuma, AZ land of 115+ degree summer days.

05-03-2003, 01:35 AM
I'm 'supposedly' getting wholesale pricing from our local Ford store and was quoted $99 for the ircm! *****, man! I didn't price the ECT yet, but will do so to see if I need to "call bull$hit".

Thanks for the help,