oh no now what?

Mont

Registered User
So I did a search and really didn't find what I was looking for so I'll ask here. I found out that my fan only comes on when my AC is on. I talked to a Ford tech and he said the fan module is bad. I called Ford and of course its obsolete. What do I do now because I really don't want to hard wire the fan and is it the box thing behind my air box on the radiator support? I have a 90 SC

And in the search I did I found these...

EEC?
ETC?
IRCM?
 
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If the tech is telling you that then he is wrong. Even if the fan runs only with the AC on it is still using the IRCM relays to turn it on. What happens if you pull the connector from the ECT Sensor...does the fan run? Are you sure you are getting to 222F in coolant temp to allow the fan to start in slow?
 
The a/c fan is a seperate relay from the regular fan relay.
I know this because in my last ircm the a/c fan relay stopped working therefore my a/c would not work.
The relay that controls your engine fan in the ircm is bad,you can get the ircm(integrated relay module) from your local parts store.
Ford obsolete's everything after 7 yrs.
 
There is no "AC FAN". There is a coolant fan at the rear of the radiator (Puller Fan) and on 94-95 SC's only there is a Fan in front of the radiator (Pusher Fan) The Pusher fan is a over temperture protection fan and comes on at around 228F. It is controlled from the PCM (engine computer) through a relay mounted on the driver's side rear part of the fender and only runs in slow speed. The Puller fan is controlled by the PCM or EEC (in early models) through slow and fast speed relays in the IRCM.
 
If I remember correctly, the fan actually has 2 windings, one for low speed and one for high speed. It sounds like your low speed fan is not coming on. So that could be a problem in the fan, in the low-speed relay within the IRCM, or with the control circuit (the ECT sensor that Duffy was talking about).

The IRCM relays are replaceable, by the way, if you don't mind a little desoldering and resoldering, deriveting and reriveting. But rebuilt units are available too.
 
I pulled the ECT Sensor and the fan turned on I even bought a new sensor and still no fan until I pull the plug. I know its getting up to temp because it almost boiled over, I also changed out the temp sensor and I know I have enough water and no air pockets too. Mine is a 1990 SC. I only have one fan so does this mean i can still walk into my parts store and buy the "ircm(integrated relay module)" or is that just for the newer SC's? and if so where is it on my car. Sorry for the dumb questions.
 
The IRCM is the black box between the radiator support and the airbox. You can get them at some parts stores, but it's probably going to be a special order.

I wouldn't necessarily assume that it's the IRCM, though, since the fan does run when you pull the ECT plug.

I don't really know the troubleshooting sequence for the fan system. Maybe Duffy can help you with that? Maybe there's a pinpoint test in the shop manual.
 
If the fan is coming on by unplugging the ECT sensor, and if its coming on with a/c, then the IRCM module is working just fine. The EEC controls the IRCM for the fans.

The stock setup has the low speed coming on at 220F, and if you are running straight up water in the car your pretty much boiling the water before it gets to 220F.

Might want to go to a 25%Antifreeze/75% distilled water mix.

Fraser
 
what one is that? i already changed the temp sensor for the gauge and I also just changed out the other larger sensor on the pass side of the car. That one was like 30 bucks. Coolant temp sensor is what Napa called it. SO whats the ECT sensor and where is it at?
 
Thats the ECT sensor if they called it a coolant sensor. Its located on the pax side and has a coolant hose coming out below it going to the heater core.

Do you have a method of reading actual temperature? If you are boiling over, it could be the rad cap is no good and a few other reasons.

Also, I just remembered that the high speed fan is the one that gets turned on when the ECT sensor is unplugged as a fail safe. This means that its possible the IRCM could be at fault if the low speed isn't kicking in, sorry for the confusion there :eek:. You need to do a KOEO test to see if both modes of the fan operate.

Fraser
 
It is NOT the IRCM cause if it was the cooling fan would not be running in slow when the AC was on.

Based on the symptoms provided

1) Fan runs with AC in Slow
2) Fan runs when ECT is disconnected.

I conclude the fan has power (No problem with fusible link) the IRCM is functional in slow speed at least, the ECT circuit seems to be working but the IRCM is not getting the signal to turn on the fan in slow at 222F

My SWAG is the EEC (internal) is the problem (most likely).

Run a KOEO test to verify. If the fan doesn't cycle you have a good indication that I am right.
 
One other possible thought is that the ECT is a thermistor meaning that as temp. increases there should be less resistance in the circuit. If there is a high resistance contact either at the sensor (unlikely) or a bad wire between the ECT Sensor and EEC (broken strands but not completely broken) or a bad connection at the EEC pin for the ECT Circuit the circuit resistance might not ever get low enough to turn the fan on.

Sorry I do not have my EVTM for your year model with me here in MI so I can't tell you the correct pin connector to be looking at ...at the EEC.
 
Could the EEC be at fault for no slow speed fan.....

I lost slow speed, but fan will work if apply power to the wires, so it isn't a fan problem.....

I have swapped out at least a dozen IRCMS and got the same results from all of them...

I disconnected the #13 wire to get slow speed fan to come on.....

When the #13 wire is connected, I only get high speed fan.....
 
Yes the EEC can be at fault, and in fact I have a theory thats the problem with most cases when the low speed stops working. When the relay shuts down, there is a small voltage spike that comes down the line, and that may be enough to damage the control circuit in the EEC.

Try another EEC and see if it works for you.

Fraser
 
Sorry Frit...I disagree with your theory. All the IRCM Schematics I have seen show a diode in parallel with the slow speed fan relay coil which is there to eliminate the inductive kick you are alluding to. It also speeds how quickly the relay will change state since it provides a "discharge" path for the coil stored current to be dissipated collapsing the magnetic field of the relay coil quicker.

I obviously agree that EEC failure can cause the fan to quit working. Since many of the output connections of the EEC are TTL (transistor- transistor logic) based....all you need is a single transistor to fail and you will no longer be able to "form" the required path to ground required to pick up the output coils of relays and such (like fuel injectors).
 
However, with that said...if the diode fails first you could be on to something....but somewhat a moot point unless you know how to disassemble the IRCM, and do the required testing/repairs.

The TTL output circuits of the EEC are buffered as well.
 
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