Cooling fan problem

Tin-Knocker105

Registered User
Did a couple searches and tried a few things but need more help.
90 5 speed 105k
Just did new head gaskets car is running great.
new 180 stat
AC not functional
the fan does work... i disconnected the ECT sensor behind the diss and check engine light came on and the fan also.
so i need help from this point what to check etc...
Thanks
tony
 
it may be ok i dont think mine kicks on till about halfway or more about the r on the guage if relay conrol module was bad i dont think it would turn on when you unplug the temp sensor there are 2 speeds maybe one of the speeds is burnt out of fan or relay contol module. im thinking when you unplug the temp sensor it just comes on low speed but not really sure , i never had any probs with fan or relay over 230 k miles .the only time mine got hot was when headgasket went around 208 k miles . i think when my harmonic balancer went around 215 k miles it ran warmer than normal and had no power
 
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It could be the IRCM or the ECT switch that you unplugged....

Unplugging the ECT switch a driving it that way could cause problems down the road, like clogged cats....
 
i am having the same prob as you in the fact that the fan dosen't work unless i turn on the AC (mine works though)or unplug the ECT sensor.i just did a engine swap so the sensor in that fact has been changed.where is the ircm.
 
the IRCM is at the pass side in front of the filter box here's a picture.
I cut the #14 wire on the IRCM so the low speed fan would come on all the time when the key's on.
I'm waiting more posts with ideas on what to check

Tony
 

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Here's what I have found

We shot voltage from the mult function relay (IRCM, CCM depending on which Ford dealer u talk to) to the fan plug. Got voltage on the dark blue wire when a/c was turned on and when the temp got high around the M. Never saw any voltage on the grayish w/orange stripe (chiltons has it labled as black and orange) wire. Then to verify fan worked on both wires jumpered the blue wire to the grayish w/orange stripe terminal on fan motor and it worked so its not the fan. So its probably either the multi function relay or whatever componet sends the signal to that relay. I am going to order a multi function relay and see what happens. Anyone else have any luck?

p.s. Where did you find that diagram?
 
I had the same problem of no fan....

I cut the #14 wire and everything is fine, for the moment.....

I am wondering if I might have a problem with the Electronic Control Assembly (ECA)..... :confused:
 
That's what I've been doing for a few years now. I cut #14 and put spade connectors on the ends. I disconnect it just during the summer months and connect it back up in winter. You really don't need it in the winter and the fact that it automatically runs when you switch on the ignition can put a drain on the battery in very cold weather and possibly hinder starting. The one draw back is that if it gets hot enough for the high speed to run, you really dont want to have the low speed winding energized as well. One way to overcome this is to splice a small wire across to the #17 (high speed), so that when the temp. sensor energizes the high speed (it ground the #17) the low will automatically disengage (grounding the #14 turns the fan off). I've also been thinking about putting a switch in-line with the #14 so I can be more selective in the spring & fall months. One thing you definitely don't want to do is have a switch/sensor (like the old MN12 cool fan switch) or separately ground the #17, because it causes a big power draw when energizing the high speed without the low speed already running. Not too bad on '89-93 models because they use a fusible link - but on '94-95 it'll blow and finally burn the underhood fuse location.
 
anyone have any luck with this?

Changed the multi mode relay and same story no fix. Changed the temp sensor in front of radiator and no fix. Going to change the coolant temp sensor (not the one for the gauge) tomorrow, but I dont think thats the cause. Dont think anything is wrong with the gauge as it reads like it always did when the a/c is turned on. Anyone have any ideas? I really dont want to cut the 14 wire and would like to get down to the source.

-Can anyone tell me which fan (high speed, low speed) is supposed to turn on first?
-what is supposed to cause this fan to turn on?
-and what is the signal path (sensor to fan) that the command signal takes?
-What I really need is a good wiring diagram.


Thanks
Wade
 
Swade said:
Changed the multi mode relay and same story no fix. Changed the temp sensor in front of radiator and no fix. Going to change the coolant temp sensor (not the one for the gauge) tomorrow, but I dont think thats the cause. Dont think anything is wrong with the gauge as it reads like it always did when the a/c is turned on. Anyone have any ideas? I really dont want to cut the 14 wire and would like to get down to the source.

-Can anyone tell me which fan (high speed, low speed) is supposed to turn on first?
-what is supposed to cause this fan to turn on?
-and what is the signal path (sensor to fan) that the command signal takes?
-What I really need is a good wiring diagram.


Thanks
Wade
I've got an 89 EVTM and I could fax you the schematics, but I don't know if they are the same for your 94.....
 
As far as the stock fans go, the low speed comes on first around 220 deg F and shuts off at around 214 deg. The high speed comes on around 228 deg and I think it goes off & back to low speed at 222. On the 94 that auxillary pusher fan is supposed to come on if the temp rises above 228. Apart form that the low speed will also run when the a/c is on, up to around 47mph, then shuts off (I guess Ford assumed that the condensor would then get enough natural air flow to not need the fan). I've found on my '94 that cutting/disconnecting the 14 wire just during the summer months works out pretty good.
 
Thanks for the continued feedback.

Thanks Big for the diagram. Turns out the early models are a little diff thatn the 94's. I found a local shop that actualy printed me out a diagram for the 94 (if anyone wants it I'll fax it out)! THe fan that engages when the a/c is on is the blue wire and according to the diagram thats the high speed side of the fan. Never see any power come to the other wire. All the wires I that I could check, are good. I may be foolish but I've decided not to give up on this till I find the source or I get tired of it and just cut the dammed wire.

Conclusions I've drawn
-Either the computer is bad and not sending the signal to the fan.
-Or the computer is not getting or is getting a faulty signal to turn on the fan.

Questions
-Is the computer the only componet to send a signal to turn on the low speed fan?
-Is the ect sensor the only sensor to send a temp signal to the computer?
-Where does the ambient air temp sensor (in front of the radiator) come into play?
-Was I told correctly that the pwertrain control modual is the same box as the electronic engine control?

Thanks again
Wade
 
the-big-e said:
I am wondering if I might have a problem:confused:

:rolleyes: :p :eek: ;) :D

I just cut my number 14 wire and crimped male and female plug ends on the wires, like David Neibert suggested, so we'll see how it does with the fan running on low.
 
Wade - I'd very much like a copy of that '94 wiring diagram. My daytime fax # is 856.424.5249
Thanks, Jim.
 
Well, after driving it to work last night and being stopped at lights where the temp needle would budge M and bring on the fan, it didn't go past O. :D

I'll see how it does later today when it's HOT.
 
Wade,

Ever fix your issues? Still have the '94 wiring diagram handy?

I'm having one hell of a time trying to figure out why my main fan cycles during KOEO, but not when the car is running or with the A/C on. Pusher works fine... especially when the temps get up above M. :rolleyes:

I'm really surprised that the blue wire is actually supposed to kick on the fan when the A/C is turned on. I'll have to check that with my voltmeter tomorrow to see if my IRCM is sending it juice. I do know that the blue wire (at the fan) splits into 2 blue wires further back into the harness. I assume if I tear the loom far enough back I'd find that both wires go into the IRCM.

Jim,

Thanks for mentioning that if #17 grounds out to trigger the high-speed, and #14 shuts off when grounded. That helps me a lot if I decide to wire it up "manually"... just have to figure out a way for a sceond thermoelectric switch to ground out the first when it triggers the high-speed relay.
 
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