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Discussion Starter · #1 ·
Yesterday when I was driving my 94 wagon around in town, the temperature gauge was up at the top end of the "NORMAL" bracket and the engine seemed incredibly hot. The cooling fan was not running. I know most of you would suspect relays right away (not saying that's not it!) but the fan works just fine when the A/C is on. It just will not turn on and cool the engine off. Does the dash gauge have to be on "H" for it to work? Or am I looking at a relay issue. Also, is it possible to install a manual fan switch (something I can wire in that will make the fan run) so I can turn the fan on whenever I want?
 

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Discussion Starter · #3 ·
I don't think my wagon has a coolant temperature switch. The computer is what controls the fan and that reads the coolant sensor. If that were bad, my CEL would be on.
 

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Discussion Starter · #5 ·
Switch seems fine. I went out again this evening and started the car and turned the A/C on. The fan runs just fine. It just does not seem to want to turn on when the engine itself is very hot. There has to be a way to wire in a switch so I can turn it on and off when I want to.
 

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My 91GT does the same thing, and the fan will turn one when I hit the A/C. But every now and then it will work properly. I suspect my issue is relays.
 

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Replacing the engine temperature sensor never hurts.
 

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You can wire the fan to a toggle switch and mount it somewhere in or under the dash and control it yourself. I've got the fan on my '88 Pony on a toggle switch and have had for probably over 10 years. Just keep an eye on the gauge when you are in stop and go traffic and turn it on when needed. I usually don't even bother turning mine on until the temperature reaches 230*+ and have never run hot since installing the switch.
 

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I have been looking at how these fans work a lot lately.
Having 4 Escorts and summer in Texas kinda guides my endevours sometimes.

The fact that your fan does work with the AC indicates the fuse and main relay (in the fuse box under the hood) are working.

When you turn the key to the ON position, you should see the fan turn about 1 revolution.
This would indicate the low speed relay is working properly.
Another check for this is to remove the cover of the main relay and, with the key OFF, trip the relay by pushing the contact.
This should make the fan run and confirm low speed relay operation.
This will also confirm a circuit through the high speed relay when it is not energized.

I am still working on how to easily check the high speed relay for both operation and continuity when energized.

Currently, when running the AC my needle does not move from around N of NORMAL on my gauge.
Without the AC, it goes to the M before a fan turns on.

I may be a bit obsessive about this since I lost the engine in my 86 EXP sitting in a drivethru window one hot summer.

Replacing the 2 prong temp sending unit is cheap easy and might fix you right up.

Bruce
 

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Discussion Starter · #10 ·
How hard is the sensor to unscrew from that little pipe? Also, can I use some sort of thread sealer on it or does it have to have a good ground to that pipe? I'll have to play with the relays and try your little trick to see if it all works. I am probably going to convert to the higher amperage relays (There's a whole massive thread on here about that I have bookmarked already!) so that way I know I won't have any issues.
 

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Don't use any sealer on the sensor, it needs to ground. Its brass so it will seal if you tighten it good.
 

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Discussion Starter · #12 ·
Good deal. How hard is it to get to the sensor and remove it from the pipe? Looks like I'd have to take the intake tube and coil pack off to get to it.
 

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It shouldn't be to hard. 4 bolts hold the coil pack on and 3 hold its bracket on. Intake tube is easy to remove. The only thing I have heard is there is a metal bar that holds the sensor pipe up. If that is loose it can mess up the ground the sensor needs so make sure its snug after you replace the sensor.
 

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madmatt2024 said:
Don't use any sealer on the sensor, it needs to ground. Its brass so it will seal if you tighten it good.
The dash gauge temp sendor need's to be grounded by the bracket, but the ECT sensor (the one that tell's the ECU when to turn the fan on) does'nt need to be grounded, it's a 2 wire sensor.
 

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93 escort starts to overheat too with no fans

Anyone figure out the problem with their escorts overheating and no fan turning on?

So far, I've replaced the ECT sensor, both low and high relays under the battery area (I used 2 universal 30/40 amp relays as suggested in that one how to that's around here somewhere). Still no fans turning on by themselves unless I didn't let the engine get too hot. It got to the M on NORMAL without a low fan speed or anything

Thing is, when I turn on the AC, the fan works just fine and cools down the car when idling. This means the relay in the under the hood fuse box is fine right? It's the only thing I haven't replaced yet.

Any help would be great. It's been friggin hot here in Bellevue/Seattle. All time record high heat today :(

EDIT: this is the how to that's on here just in case anyone else is wondering
http://www.feoa.net/modules.php?name=Fo ... ic&t=35441

EDIT: tested the cooling fan relay in the fuse box and it's operational. took off the cover and pressed on the thing and the low fan relay came on. stumped
 

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Discussion Starter · #16 ·
Have the same problem. I repaired my relays and the fan only works with the A/C on. I think it has to be a problem in the computer.
 

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I'm battling the same issue... adding a manual switch brought me piece of mind.

Wiring in a toggle without altering the factory harness is easy enough. Get the crimp on tap that lets you attach a new wire to an existing one without cutting it. They crimp on with a pair of pliers and have a snap over cover to insulate the blade you just crimped over the two wires.

That tap you put onto the hot right at the fan connector. I attached to the yellow/low speed wire. The new wire goes to the car interior to your new toggle.
With a fuse holder, attach a second wire to the positive post on the battery and run that to the interior as well. I used a 20 amp fuse. Putting a fuse in there is just basic safety. Electrical fires are ugly, especially if it consumes your car.

The switch I mounted to the plastic shroud beneath the steering column. It is right between my knees, a tad awkward cuz I can't see it w/o leaning over, but there isn't any chassis metal in the way right there.
I bought a lighted switch so I had to add a third wire that goes to a nearby chassis screw under the dash.
When the switch is on, it lights up as a visible indicator.

The toughest part of all this was drilling through the firewall from the engine compartment. I actually drilled from inside to the exterior, left of where a clutch pedal would be. That whole area is crowded and I was concerned about drilling into something I didn't want to.
The whole thing only cost about $12 and I have extra wire and terminals for future use.

FOOTNOTE: I did the relays today and learned the pilot light feature of my toggle blows the 40 amp fan fuse! Doesn't make sense to me that it would do that... in fact I was hoping relay power feeding back on my new line would light up the switch, showing me when the fan was on via the factory system. It cost me ($3 x three) going over it all before I was sure that was the issue. Needless to say, I'll be monitoring it all for the next few days to be sure all is well.
Regardless, the switch will be staying for my own peace of mind. I do expect I could put in a diode on my feed to the fan motor and that would allow me to leave the pilot light feature working but right now I'll do without.
 

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Discussion Starter · #18 ·
This may be my fix as well. I'm not going to spend the time or money on new sensors and computers right now because I don't have the time or the money!
 

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ethangsmith said:
I'm not going to spend the time or money on new sensors and computers right now because I don't have the time or the money!
The sensor is only about $12
 
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