North American Turbocoupe Organization



Need Cooling Fan Info
Big Boost Daddy Offline
Junior Member
#1
Looked at past posts and learned some but not enough.The main fan does not turn on at all,but it will if I power it up externally.It does not turn on when you start the car and will not turn on when you unplug the coolant temp plug,although the secondary fan does power up when you unplug the sensor.The main fan does not come on when you turn on the a/c(which does work fine)and the car will overheat if left to.I'm guessing the multi-function relay on the right fenderwell may be the culprit, but at $100 I don't want to guess.Any sure-fire electrical tests I could make? Thanks for any input oh great turbo gods.BTW,hard wiring the fan through a relay is a distinct possibility, but would rather have it work the right way.

------------------
Son's car:88 Turbocoupe 5spd,pitifully stock
My car:88 Mustang GT 5spd,1 5/8" headers, hiflow h-pipe w/cats,2 1/2" dynomax cat-back,Hurst shifter,K&N panel,ponies,Cervinis Stormin Normin hood,3.27 gears
Son's car:88 Turbocoupe 5spd,pitifully stock
My car:88 Mustang GT 5spd,1 5/8" headers, hiflow h-pipe w/cats,2 1/2" dynomax cat-back,Hurst shifter,K&N panel,ponies,Cervinis Stormin Normin hood,3.27 gears
Reply

jiggyincanada Offline
Member
#2
This sound exacly like my car. Can somebody give us rundown on where the relays/fuses/whatever else runs these fans are. I also checked past posts but to be honest I'm more confused now than ever. I'd rather have it run proper also.

------------------
THANKS,JIGGY or sometimes her Dad, Tank.
16 FEMALE and proud of it!
1987 TC Dark Grey Bone Stock except for stereo. Plan on Gillis valve, K&N and whatever else I can afford. Maybe a 302HO.NOT!
OOPS! I BOOSTED, ONE TOO MANY TIMES, AGAIN....
Reply

Jeff K Offline
Administrator
#3
OK, guys and girls, here is the low down on the fan system on the 87-88 TC. Both fans are controlled by the EEC via the IRCM (integrated relay control module), which is the black box with about 24 wires coming out of it. To test the aux fan (smaller drivers side one) Pull the connector off the A/C pressure switch, which is in the high side A/C line near the VAM. Turn the key on, and jumper the 2 pins in the connector you just removed. If the aux fan runs, the relay in teh IRCM is OK.

To test the main fan (big drivers side one) and its relay, you will have to cut a wire, but you can easily splice it back together. Locate the Tan/Orange wire going to pin 14 of the IRCM. With the key on, probe the wire with a stick pin, and see if it has 12V on it w.r.t. ground. If it does, cut the T/O wire, and the fan should run. If it runs, the main fan relay in the IRCM is OK.

If both these check out, then the EEC is not sending a signal to the relays in the IRCM. Either a wiring problem exists between the IRCM and EEC (T/O and Y wires), or the EEC thinks the engine is cooler than it really is due to a bad ECT sending false temp info to the EEC.

If the "jumper and cut" test does not turn on the respective fans, the IRCM is probably bad, but before replacing it, be sure the heavy yellow wires going to pins 3 and 4 of the IRCM are hot at all times. Test this with a test light, not a voltmeter.

Running a code test may show a bad ECT, but only if its temp readings are WAY out of wack. In other words, the ECT may be reading temp as lower than it really is, but still not set a code.

------------------
Jeff Korn

88 Turbo Coupe: Intake and exhaust mods, T3 turbo at 20 psi, forced air intercooler, water injection, bypass valve, Ranger roller cam, subframes, etc., etc.. // 86 Tbird 5.0 (original owner): intake, exhaust, valvetrain mods, 100 HP nitrous, ignition, gears, suspension, etc., etc.... // 91 Escort: Bone stock winter car // 00 Windstar (wifes vehicle)
Jeff Korn

88 Turbo Coupe: Intake and exhaust mods, T3 turbo at 24 psi, forced air IC, water injection, BPV, Ranger cam, subframes, etc., etc.
86 Tbird 5.0 (original owner): intake, exhaust, valvetrain mods, 100 HP N2O, ignition, gears, suspension, etc., etc.
05 Taurus SEL Duratec daily driver
04 Taurus Duratec (wifes car)
02 Pontiac Grand Prix GT
95 Taurus GL Vulcan winter beater
67 Honda 450 Super Sport - completely customized
Reply

Pete D Offline
Administrator
#4
There is one relay for each fan in the Integrated Relay Control Module (IRCM) which is the big black box on the front of the passenger side strut tower. Also in there are the power relay for the computer, the fuel pump relay and one other. At least one of our members has replaced relays rather than buy a new/rebuilt? box. From his verbal description it takes some electrical finesse. but I can't tell you more. I'll send him an e-mail and see if he will post something on it.

Here is some info for testing the relay for the driver's side fan, it's from Jeff Korn:
"Here is how to check the relay for the drivers side fan (smaller one) in the int. controller: Find the PINK wire at terminal 17 of the ICRM. Probe it with a pin, like when checking the TPS voltage. Run a jumper from the probe pin to ground with the key on. When the pink wire is grounded, the lower, drivers side fan should run.
If the fan runs, the IRCM is OK. I have tapped into this pink wire, and use a relay to ground this wire whenever the HVAC function lever calls for A/C, so I have both fans running when the A/C is on. Motor stays nice and cool this way, and my 130A alt easily handles the load."

To test the other relay, do the above to the tan wire w/ orange strip.it goes into the 2nd from the bottom position on the I/C side of the connector. Not 100% on that but I did this recently and I think that's the one.
Pete


------------------
Pete Dunham


Reply

jiggyincanada Offline
Member
#5
Thanks Jeff! That's what I was looking for in an answer! Just one more thing. Should the small fan come on when you run the codes? Mine does.

Could you please write a post with EVERYTHING you know about tc's. lol [Image: smile.gif]

------------------
THANKS, JIGGY or sometimes her Dad, Tank.
16 FEMALE and proud of it!(me not my Dad)
1987 TC Dark Grey Bone Stock except for stereo. Plan on Gillis valve, K&N and whatever else I can afford. Maybe a 302HO. NOT!
OOPS! I BOOSTED, ONE TOO MANY TIMES, AGAIN....
Reply

Jeff K Offline
Administrator
#6
Yes, one of the fans runs during a code check... but I dont remember for sure which one it is.

------------------
Jeff Korn

88 Turbo Coupe: Intake and exhaust mods, T3 turbo at 20 psi, forced air intercooler, water injection, bypass valve, Ranger roller cam, subframes, etc., etc.. // 86 Tbird 5.0 (original owner): intake, exhaust, valvetrain mods, 100 HP nitrous, ignition, gears, suspension, etc., etc.... // 91 Escort: Bone stock winter car // 00 Windstar (wifes vehicle)
Jeff Korn

88 Turbo Coupe: Intake and exhaust mods, T3 turbo at 24 psi, forced air IC, water injection, BPV, Ranger cam, subframes, etc., etc.
86 Tbird 5.0 (original owner): intake, exhaust, valvetrain mods, 100 HP N2O, ignition, gears, suspension, etc., etc.
05 Taurus SEL Duratec daily driver
04 Taurus Duratec (wifes car)
02 Pontiac Grand Prix GT
95 Taurus GL Vulcan winter beater
67 Honda 450 Super Sport - completely customized
Reply

GT350R Offline
Senior Member
#7
It you would like to see a wiring diagram while you are reading Jeff's (the wiring god) post, I have it on my site. Just click the link in my sig below.

------------------
GT350R
#1978 20th 2.3 Turbo T-top
#3608 20th 2.3 Turbo T-top
WAY too many TC's and other mustangs!

My Garage
GT350R
(sold Sad ) 87 5speed, Motorsport head, [email protected]+2, [email protected], gutted or ported everything & all the typical junk.
84 Gt350 2.3T T-top
84 Turbo GT 418rwhp

My Garage
Reply

Big Boost Daddy Offline
Junior Member
#8
Thanks so much for the info.I have my testing cut out for me tomorrow. It's going to be a beautiful day out here on the east coast so I'll probably be all over the Bird. I borrowed a Snap-on Star tester from one of my techs so I can pull any codes. I'm ready and psyched from all your great tips. I really appreciate guys like you.

------------------
Son's car:88 Turbocoupe 5spd,pitifully stock
My car:88 Mustang GT 5spd,1 5/8" headers, hiflow h-pipe w/cats,2 1/2" dynomax cat-back,Hurst shifter,K&N panel,ponies,Cervinis Stormin Normin hood,3.27 gears
Son's car:88 Turbocoupe 5spd,pitifully stock
My car:88 Mustang GT 5spd,1 5/8" headers, hiflow h-pipe w/cats,2 1/2" dynomax cat-back,Hurst shifter,K&N panel,ponies,Cervinis Stormin Normin hood,3.27 gears
Reply

Jeff K Offline
Administrator
#9
Quote:Originally posted by Jeff K:
OK, guys and girls, here is the low down on the fan system on the 87-88 TC. Both fans are controlled by the EEC via the IRCM (integrated relay control module), which is the black box with about 24 wires coming out of it. To test the aux fan (smaller drivers side one) Pull the connector off the A/C pressure switch, which is in the high side A/C line near the VAM. Turn the key on, and jumper the 2 pins in the connector you just removed. If the aux fan runs, the relay in teh IRCM is OK.

To test the main fan (big drivers side one) and its relay, you will have to cut a wire, but you can easily splice it back together. Locate the Tan/Orange wire going to pin 14 of the IRCM. With the key on, probe the wire with a stick pin, and see if it has 12V on it w.r.t. ground. If it does, cut the T/O wire, and the fan should run. If it runs, the main fan relay in the IRCM is OK.

If both these check out, then the EEC is not sending a signal to the relays in the IRCM. Either a wiring problem exists between the IRCM and EEC (T/O and Y wires), or the EEC thinks the engine is cooler than it really is due to a bad ECT sending false temp info to the EEC.

If the "jumper and cut" test does not turn on the respective fans, the IRCM is probably bad, but before replacing it, be sure the heavy yellow wires going to pins 3 and 4 of the IRCM are hot at all times. Test this with a test light, not a voltmeter.

Running a code test may show a bad ECT, but only if its temp readings are WAY out of wack. In other words, the ECT may be reading temp as lower than it really is, but still not set a code.


There is a much easier way to check the operation of the main (pass side) fan that doesnt involve cutting / grounding wires! When I wrote the post quoted above, I forgot completely about this!!!!!! Here goes: Run the KOEO EEC diagnostic test. During the test, the main fan should run. If it does, the IRCM, and all the fan main wiring is functioning correctly all the way to the EEC. If the main fan comes on during the KOEO test, but fails to come on when the motor gets hot (stock temp gauge up about 1/2 way), the most likely cause is a bad ECT. Sorry about that one, guys.... I had long day yesterday.

------------------
Jeff Korn

88 Turbo Coupe: Intake and exhaust mods, T3 turbo at 20 psi, forced air intercooler, water injection, bypass valve, Ranger roller cam, subframes, etc., etc.. // 86 Tbird 5.0 (original owner): intake, exhaust, valvetrain mods, 100 HP nitrous, ignition, gears, suspension, etc., etc.... // 91 Escort: Bone stock winter car // 00 Windstar (wifes vehicle)
Jeff Korn

88 Turbo Coupe: Intake and exhaust mods, T3 turbo at 24 psi, forced air IC, water injection, BPV, Ranger cam, subframes, etc., etc.
86 Tbird 5.0 (original owner): intake, exhaust, valvetrain mods, 100 HP N2O, ignition, gears, suspension, etc., etc.
05 Taurus SEL Duratec daily driver
04 Taurus Duratec (wifes car)
02 Pontiac Grand Prix GT
95 Taurus GL Vulcan winter beater
67 Honda 450 Super Sport - completely customized
Reply

jiggyincanada Offline
Member
#10
I give up! what is "ect" and where is it? [Image: confused.gif]

------------------
THANKS, JIGGY or sometimes her Dad, Tank.
16 FEMALE and proud of it!(me not my Dad)
1987 TC Dark Grey Bone Stock except for stereo. Plan on Gillis valve, K&N and whatever else I can afford. Maybe a 302HO. NOT!
OOPS! I BOOSTED, ONE TOO MANY TIMES, AGAIN....
Reply





Users browsing this thread:
1 Guest(s)



Theme © iAndrew 2018 - Software MyBB