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Topic: Cooling issues (Read 996 times) previous topic - next topic

Cooling issues

Well my 87 turbo coupe is at it again, it was over heating at one point because the temp sensor was not kicking on the fan, so i fixed that and it was "better" as in it was maybe a quarter below hot when it was sitting still. Now its doing it all over again, like the fan wont kick on, one of them will turn on when i turn on the a/c, but what els could it be?  The fan itself?

Cooling issues

Reply #1 –
If you have a fan relay i would check that
FOXLESS!!

1994 Lincoln Mark VIII

Cooling issues

Reply #2 –
I have been having the same problems here recently but I havent had time to sort out the cause.  heres some really good info http://www.turbotbird.com/techinfo/Cooling_Fan/CoolingFan.htm

Cooling issues

Reply #3 –
i looked through all your posts and this is the first cooling issues you have posted.

It seems like your problem is within the Integrated Controller Module based on the symptoms.


The secondary fan relay ****COIL**** does indeed get a ground by three means in parallel.  The Pink wire on the integrated controller module goes to the following:
1-ac presure switch
2-ac head compressor switch
3-EEC pin 52.

The primary fan relay ****COIL**** gets a ground from the EEC pin 55.  The tan/org wire goes to pin 55.

I think your focus should be on the primary fan relay containted in the controller asembly.
To test, I would do the following:
-leave car off with no key in
-jumper power to the red wire (pin 34)
-jumper ground to the tan/org wire (pin 14)
your primary fan should come on.
**remember, do not turn on your key or car.

If it does not, chime back.
A far simpler solution would be to check the diodes on the schmatic because they may be blown.
worse case the eec is fubar and not supplying a ground properly to the primary relay contained in the controller.

Cooling issues

Reply #4 –
and the location of the Integrated Controller Module

Cooling issues

Reply #5 –
and for those of you wondering WTF!!

It's your turn to figure out how the eec power relay gets a ground:D

Cooling issues

Reply #6 –
Quote from: jcassity;249166
and for those of you wondering WTF!!

It's your turn to figure out how the eec power relay gets a ground:D


The "voltage inverter" inverts the "Hot in Start or Run" to provide the negative voltage for the relay coil.

The same applies to the primary fan relay. The EEC provides a plus voltage to pin 14  and the inverter inverts it.

Is there enough slack in the cable harness to reverse the fans?

Can the relays in the integrated controller module be swapped?
Can't tell if the voltage inverter controlled relays have 12v coils or not. May be safer to swap the primary fan relay with the EEC power relay.

Cooling issues

Reply #7 –
that was my gut feeling that the difference in potential would give the eec relay a ground point,, it just seems to be a rather complicated route around the block in my opinion when the same thing could be achieved with a ground point.

I am sure there is some odd purpose to the power path.  I think with a bonded eec relay coil to chassis would have had the same effect for what is being controlled off its contacts.

I would bet its safe to say they are 12v coils.  Ive never had one apart and I am not really sure how often this piece part has been brought up here for discussion.  I know this is the first time i personally have ever looked at this module because it is specific to the TC.  Heck, even the eec control relay is inside this little box !

anyway, i hope someone finds this thread useful because if and when my son owns a tc, atleast im familiar with what a goofy layout it is.  It took me like 30 min trying to give that eec a ground before the thought crossed my mind that ford may have taken great delight in making best use of pulling the ref voltage low so the eec relay grounds on an engineered polarity flip and thats all.  I honestly think its stupid and if I had this problem, the first thing i would do is disconnect the tan/org wire from the controller.  Next i would wire the controllers pin 14 to ground.  this would cause the fan to run full time though which might be good or bad depending on how you view it.  If the fan did not come on then I would know the inverter do hicky was bad.  That would force me to jumper from the neg side of the physical relay coil to chassis which would again result in the fan running full time with the key on.

A replacement controller would be the perm fix if the inverter on the coil side of the primary fan relay is bad.

One thing is certain, i would be checking those diodes as well because where they are, it would not be too hard to spike them with an improper jump start ect or random arching / sparking.  They are easy to read and could be had at radio shack for pennies on the dollar.