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vivisex666
05-04-2004, 02:26 PM
first, i have a '94 sc;
my fan doesnt come on w/o the air being on. i put in a new 180 thermostat, no change. from searching this site, i figured the ect was the next logical thing to change.
i was under the impression that the ect sensor was in the thermostat housing. but i'm being told by my auto parts store that that sensor only controls the guage. and the sensor that's connected to the computer and controls when the fan comes on is in another location.
is this correct? any idea where i can find this missing sensor?

Ken Seegers
05-04-2004, 02:35 PM
first, i have a '94 sc;
my fan doesnt come on w/o the air being on. i put in a new 180 thermostat, no change. from searching this site, i figured the ect was the next logical thing to change.
i was under the impression that the ect sensor was in the thermostat housing. but i'm being told by my auto parts store that that sensor only controls the guage. and the sensor that's connected to the computer and controls when the fan comes on is in another location.
is this correct? any idea where i can find this missing sensor?


That is correct....It is located on intake manifold on the passenger side near the A/C compressor. It will have a heater hose coming off it.
Later
Ken

vivisex666
05-05-2004, 09:13 AM
found it, thanks. easy change. but fan still doesnt come on. is there a relay i need to check? any other i ideas? or did i maybe just get a bad sensor? (i've had a bit of a problem with getting bad parts lately. i just went through 4 altinators. all defective.)

TbirdSCFan
05-05-2004, 02:23 PM
Yes, there is a relay. Two of them actually. One for the low speed setting and one for high. Both are sealed inside the Integrated Relay Control Module (IRCM) which is the black box just in front of the air cleaner. If your A/C works, you can try just turning it on and the fan should run. It is the EEC which switches the fan speeds based on the readings from the ECT which you just replaced.

Digitalchaos
05-05-2004, 04:51 PM
If you unplug the ECT sensor, the EEC should engauge the high speed fan. As TbirdSCFan said, if you activate the AC your low speed fan should turn on.

Along with the IRCM, its possible your fan motor is bad.

vivisex666
05-12-2004, 10:28 AM
If you unplug the ECT sensor, the EEC should engauge the high speed fan. As TbirdSCFan said, if you activate the AC your low speed fan should turn on.

Along with the IRCM, its possible your fan motor is bad.

Using the two tests, I found that both the low and high speed fan turn on. wouldnt this alone indicate that the motor was working? The wires and connection look good as well.

i just found this on a similar thread: 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.
that i did, and fan comes on. so its not the IRCM??? now i'm really confused. :confused:

HSKR
05-12-2004, 02:43 PM
When exactly are you wanting the fan to come on?? It shouldn't turn on by itself unless the water temp gets around 230 degrees. Putting in a 180 t-stat won't change the operation of the fan, and neither will changing the temp sensor.

vivisex666
05-12-2004, 02:55 PM
When exactly are you wanting the fan to come on?? It shouldn't turn on by itself unless the water temp gets around 230 degrees. Putting in a 180 t-stat won't change the operation of the fan, and neither will changing the temp sensor.
the fan does not come on at all under normal operation. the temp guage will climb to the red and the engine will overheat. however, when i turn on the automatic climit control, the low speed fan turns on. and if i unplug the ECT, the high speed kicks in.
as far as the t-stat goes, it got replaced bec the gasket on the housing went bad and started leaking.
the ect got changed bec the old one looked real bad, and the info i was finding sugested that it could be the problem.

HSKR
05-12-2004, 03:50 PM
Okay, I was reading into it like you were trying to get the fan to come on sooner. Might be a bad connection with getting the signal from the sensor to the EEC.

hockeydad2
05-21-2004, 01:56 PM
Okay, I was reading into it like you were trying to get the fan to come on sooner. Might be a bad connection with getting the signal from the sensor to the EEC.
hi vivisex666,
have you found the problem ? i just bought a 93 sc and it has the same problem with the fan not coming on unless you have the ac on. i will unplug the ect connector tonight and see what happens. thanks, bob

hockeydad2
05-21-2004, 03:21 PM
hi vivisex666,
have you found the problem ? i just bought a 93 sc and it has the same problem with the fan not coming on unless you have the ac on. i will unplug the ect connector tonight and see what happens. thanks, bob
couldn't wait until tonight, i pulled the plug on the ect and the fan came on.
so it's doing the exact same thing as yours.
SO, it seems to me that the ECT is in a "closed contact mode" when the engine is cool or under a certain temperature (manual says lower than 222 degrees F), when the coolant reaches a certain temperature (above 222 degrees F) the ECT goes to a "open contact mode" and stays open (fan running) until the ect says the coolant temperature is lower that 214 degrees F. The manual says that the fan is controlled by both the CCRM (constant control relay module) and the PCM (powertrain control module). i will ohm out the ECT tonight when the engine is cold and watch it until the temperature gauge reaches the "M" or a little passed it. I'll let you know what i find. bob

TbirdSCFan
05-21-2004, 07:07 PM
Maybe we're saying the same thing but at the risk of repeating it, according to the wiring diagram, the ECT is a variable resistor just like the temp gauge sender. The voltage across it or current through varies with temperature.

The EEC samples that level to get the engine temp and figure out how much fuel to meter, and when to turn fans on among other things. When you disconnect it, the EEC goes open which probably causes the voltage to shoot up as if the resistance went to maximum, and then the fan kicks in.

If I suspected a problem, I'd go ahead and replace it. As simple as it is, it should be cheap like in $10 or less.

vivisex666
05-25-2004, 01:20 PM
i did end up fixing the prob, by accident actually. first let me say that i was also having an issue with getting bad altinators. in my struggle with the 3rd and 4th one, i began to inspect everything. i found a bad fuse and one that was a little charred in the black fuse box by the battery. it didn't fix my altinator prob but that may be what fixed the fan. i also replaced the ect sensor bec it was all coroded and looked pretty bad. it may have been that. not exactly sure. all scientific method went right to hell.
my suggestion is first to check the fuses. if they're fine go to the ect. its not that expensive. i think it was like $15. if you change it, make sure you blead the coolant system because air gets in when you do it.
good luck. let me know how it turns out.
-ian

hockeydad2
05-28-2004, 04:29 PM
hi all,
i ohmed out the ect sensor and checked the voltage at the connector with the engine cold and at normal running temperature (temp needle in the middle). the readings, both ohms and voltage were NEAR what the manual says they should be (no tolerances given?). i then pulled another ect from a engine i got from the junkyard and installed it. the fan still didn't come on.
i did notice, when i removed the ect that the coolage level was about one inch or so from the top of the fitting. so i removed the ect again and filled the fitting with coolant until it overflowed. i then reinstalled the same "junkyard engine ect". NOW THE FAN COMES ON when the temperature needle is on the "M"??
i have two questions, do you guys think it's possible that there was trapped air in the ect fitting that didn't allow the coolant to reach the ect sensor tip?
the second question is, on a 93, is the "M" about the right time for the fan to come on?
i'am thinking about buying a FORD ECT ([email protected]) here in san jose, ca. because the ect that came on the car is an aftermarket and looks new. the resistance readings are "close" to the "junkyard engine Ford ect", but the fan doesn't work with it. i hope to post pictures of the car soon because this is the first "teal 93 sc i've ever seen. thanks, bob