Fan "stuck" on high
 

Still waiting in the dark for my bently manual....

The fan comes on high as soon as you turn the key on. Unplugging the temp sensor in the rad won't make it turn off, nor will unplugging the temp sensor in the head.

My fan is stuck on high. Pulling the purple fan relay will cause the fan to go off. Turning on the AC (with the purple relay out) won't kick the fan on. Swapping in a yellow relay in place of the purple one will kick the fan back on.

Something is telling the high fan to come on as soon as the car is powered up.

Ideas?

it's possible that the fan wasn't operating right before you got it, so rather that fix it correctly the PO just rigged it up so that it's on all the time, I'd start by checking the wiring harness for electrical tape, heatshrink or butt connectors

maybe you have to jumper the plug to the rad temp sender.. maybe a/c high pressure switch? So it sounds like a bentley manual is the way to go, I was hoping the electronic manual off ebay was going to have wiring diagrams but no..

Does it stay on even with the car going? cold or warm? or just when your put the key "on"?

Sounds like a wiring issue for sure. Since the relay has been eliminated (although I would prefer a correct relay for the test).

Wiring has already been mentioned.

Is this a stock ti? If so, pull fuses until yoiu find the one or two that kill the fan.

Then check the wiring diagram (I have them if you [or anyone else] needs them) to see how it SHOULD be for your year car. It might be something as simple as the engine harness being changed to fix some other problem and the incompatibility is sending an A?C on signal all the time to the fan...

Just when the key is "on". Cold or hot, always on.

Stock TI, I just replaced the engine wiring harness as I bought the car with a melted on. PO (or "mechanic") had wired in a universal O2 sensor wrong, shorting/melting the harness.

When I go to swap the car, I'm tempted to replace the front harness from the bay (body harness) if it's a separate piece from the interior/behind dash harness.

What year is it?

I think I still have a stock ti harness (4/1998) kicking around somewhere...

If that is good for you, I will see if I can find it.

Not this weekend as I am traveling, but next week perhaps...

Sure, let me know :)

-ps, PM box is full

cracker - the harness I sold you will be the only one you will be able to use since you have an M42, you can only use a 1995 Ti harness. I can't remember if the fan connector is on the body or the engine harness, but get your manual out and trace the connection back to the fuse box, make sure you have a proper connection and go from there.

Fan connector is on the body harness...

PM box cleared out too...

Sounds as if you can't use my harness anyway, if you have a 95 ti..

Thought I had this one licked....

I had the oil pressure sensor plug and another one swapped. Is the front sensor in the head is for the gauge, and the other sensor is for the ECU coolant temp?

In any case, I now have a working oil pressure idiot light, and the car runs about 200% better now that the ECU is fueling the car based upon the correct temp. Weird.....I haven't replaced the front knock sensor but the check engine light is out now..

Now that I think about it... I'm wondering if I've got the gauge and ecu temp sensor leads swapped around. Can someone verify the gauge sensor as the front one, and that the colors are brown black and brown red?

RealOEM just has them listed as "temp sensor" and "Engine coolant sensor"

What turns the HIGH speed fan on is the AC switch. When the compressor runs, so is HSF. The temp sensor switch on radiator
regulates its on/off after the signal. ECM 68 operates the low
SF signal. My LSF connector melted and now I get no LS signal from ECM black/green. As far as relays, they can fail in the open or closed position. Shut off your AC and see if fan quits.

Thanks Bill, but shutting off the AC doesnt cause the fan to quit running.

I've messed with it all I'm going to....it's not hurting anything at this point so for all I care it can run as much as it wants.

In engine compartment in dr side box is purple HSF relay ++0113.
My LS is out/replaced so if ya need a HS if yours frys, look me up! I should have done that (?) to Mine, and not worry! I think my LS burned my ECM internal.