still have cooling fan issues

I have an 88 TC and have gone through almost every scenario I can think of. I replaced the ECT, the sending unit, done KOEO tests and still the do NOT work when the engine is hot. They come on when the car is first started, they come on when the AC is turned on, and they come on during the KOEO test. I've read posts of a relay under the dash behind the glovebox for earlier models. Does mine have on and could this cause the problem?

Your 88 fan relays are in the IRCM, the big black box with all the wires on the front of the passenger side strut tower. Have you checked/cleaned out the coolant fitting on the bottom side of the lower intake? If those clog then water can't flow past the ECT and it won't "see" the hottest coolant

I think if it comes on at all by itself like you say it does then there's nothing wrong with the circuit or relays. Have you let it get hot enough for the secondary to come on? How hot is hot when you expect it to turn on? How are you measuring that hot?

Like Pete said, if the coolant flow past the ECT is not good or is clogged up, your fans will not work correctly.

Coolant is supposed to flow from the head, through the lower intake (and past the ECT), and out the bottom of the lower intake, joining the water out of the oil cooler. This path being clogged could very well be your problem. I've heard of it being completely stopped up before.

HTH.

You may have a coolant temp sensor that is way off. The gage uses a seperate sensor. I had a TC that would go into the red and freak me out. Check it with a a radiator thermometer and it was running at 190F.

I've replaced the sending unit also so the gauge is working. Hot would be the fact that the car stays in the normal zone while driving. If I stop and let the car idle, the gauge goes all the way to the highest point. No fans come on at all. As soon as I turn on the AC, after about 2 mins of the fans running, the temp is right back in the normal zone.

If you have an infared thermometer put it on the t-stat housing. If not, like Hawk said, stick a thermometer in the radiator. You need to confirm it's not the notoriously inaccurate gauges. It's not the sender, the gauge cluster is a known issue. Sometiimes mine goes all the way into the red while my aftermarket shows 210.

The stock gauge is about as accurate as sticking your finger in the radiator and guessing how hot it is. I had a IRCM issue that had the EXACT symptoms you describe. Fan would come on when you start the car, would come on with the a/c on, but as far as coming on when the temp got up there, no good. I started out with the thermometer in the rad. Stock gauge was all the way up, thermometer said more like 210. After seeing that, I put in a Autometer temp, oil and boost gauge. Good thing for the temp gauge as the IRCM went bad way after I put in the gauge. I wouldn't have beleived the stock gauge and probably would have killed the motor. Good luck.

BTW, I also got a bad new IRCM the first time. If you wiggled the connector, you could make it go on and off. I don't trust ANY new part these days as being good. I went through 4 new Motorcraft TFI's a while back and NONE of them worked. The guy at Rockauto said it must be something else. Well, I STILL have the old cheapo TFI I yanked from my former SVO in there for probably about 15000 miles now with NO issues. Most of you guys probably remember that thread. All I know now is that just because it's new, don't mean it's good.

I'll have to switch it back to my original gauge. I changed it a few months ago when the gauge stopped working totally. I then replaced the sending unit and that fixed the problem. Does anyone have a TC that the fans never run and the car actually runs cool enough? I have a 190 stat in too.