dalynchmob

Hey guys just recently my fans started staying on. I haven't done any mods. Just noticed it yesterday. They are on any time the car is running and it wasn't doing it before. It's great in traffic cause my car stays right at 180 all the time now. But i worry about burning up my fan motors and don't like the noise. Anyone else had this happen? If so what's the fix?

shoebox

If the SES is on, the fans will be, too. Have it scanned.

(You really need to provide at least some basic info of what car you are talking about)

dalynchmob

Light not on. Yes the light works but it's not on when the car is.

Injuneer

As Shoebox suggested..... you need to add some basic info about your car - year, model, engine, trans and any major mods. Without that, people are just making wild guesses as to what is wrong.

Why not add a "signature" with the basic info, so we can help you?

dalynchmob

Ok i got a 1994 z28 M6 with 145k miles on it. It's bone stock. The a/c nor the defroster are on and my fans run when the engine is running. They do not come on when i turn the key to the on position but only if the car is running.

Injuneer

Its a common problem when DTC codes are present. Not all DTC codes turn on the SES light. Might be worth putting a scanner on it to verify that there are no codes present. While the scanner is hooked up, look at the coolant temp sensor reading and see if it is correct.

And just for the heck of it, check fuse #7 in the box under the hood.

dalynchmob

Ok will do. I'll let you know what my findings are.

dalynchmob

Ok here's what we got. None of the auto parts stores around here have an obd1 scan tool that i can use and don't feel like paying 80 bucks for some shop to use thiers when the part is most likely $12. Fuse 7 under the hood is good. All relays are working. Which one of the following tells the computer to turn the fans on. The temp sensor or the temp sender? I'm taking a guess and saying sensor.

Either way they both cost about 12 bucks.

JAB

The ECT sensor is the one in the water pump which let's the PCM know the temp but it was bad it should be setting a DTC and making the SES light.

1994formy

My ect sensor was bad. You can check it with an ohm meter and reference that chart on shoebox's site.
Mine was reading like 10 degrees when it was over 50 degrees outside. It never lit the ses light, though when I replaced it it cured several issues...... Hard start, torque converter not locking up, high idle.
My fans still don't come on though. If I let it sit and idle, it'll get up to the red according to the gauge and no fan action.

dalynchmob

Well i broke down and bought the sensor and that's not it either. I did try and use my a/c the other day and it didn't seem to be working so i put a gauge on it and it was full but i discovered that the a/c compressor clutches aren't engaging. I'm sure this is prob the cause of the fan problem but it i don't think it's major cause it's not throwing a ses light. Anyone?

dalynchmob

Getting the mechanic to look at it tomorrow i'll post up his findings in case anyone else has this prob in the future.

dalynchmob

Well it was a bad sensor. The a/c high pressure sensor. Fixed the fans and the a/c. The sensor was sending a high temp reading to the pcm and telling it to turn the fans on. 41 dollar sensor and 114 labor to troubleshoot and install. I hope anyone having this prob reads this and saves themselves some $$.

shoebox

A scanner's worth is pretty obvious in this case.

dalynchmob

Doesn't a scanner only show you what's wrong if there is a ses code?