[DaveMan]

Trying to help a friend out but finding and fixing this.

The radiator fan runs as soon as the key goes to run position, engine running or not. It doesn't run with the key off.

I have searched around and found the A/C high pressure cutoff switch next to the radiator on the drivers can go bad and cause this. I unplugged it like said and the fan still runs. I unplugged the low pressure one too and it didn't help. If I remove the 40a fuse or the relay in the junction under the hood the fan stops. I looked around to make sure the fan wasn't wired in directly from a old owner and it's not.

Also we have a snap on scanner at work and the coolant temp sensor seems to be working right but the car never warms up because of the fan always being on.

I want to check the high and low speed relays under the hood but have to find them first. How do I check them? Not much for the electric end of things. Or if anything else can cause this let me know.

Thanks

 

[denisond3]

The two fan relays are buried in a 'pocket' inside the fender on the driver's side. You have to pull out the air filter housing, then you will be able to see them.
Each of them is controlled from the computer (the ECC), but without having the wiring diagram, I think it would be really confusing, due to the way the low and high speed fan control take place.

Look in the How-To forum for this topic:
HOW TO: change cooling fan relays to regular ones.

Even if the relays arent the real problem, the posting has good pictures.

On my 92 Escort, the fan began coming on as soon as the ignition was turned on (even with the engine stopped), but the problem went away within a month. This was in the summer time. I dont know why it did this, but even with the fan running all the time, the engine still got warm enough for the temp gauge to be reading almost at the normal temperature. Even with the fan running full time, the needle on the gauge should probably point at least to the 'n' in normal. If not, you might have a stuck thermostat. Sometimes folks will take the thermostat in an attempt to solve a chronic overheating problem. I've done it myself, though its never the real solution.

 

[zzyzzx]

even with the fan running all the time, the engine still got warm enough for the temp gauge to be reading almost at the normal temperature. Even with the fan running full time, the needle on the gauge should probably point at least to the 'n' in normal.

This is the normal operating temp with it warmed up:

 

[PonyExpress]

pretty close to normal... straight up would be more typical, but that isnt bad considering the fan is always on.

btw my 95LX does this too.. and although my temp sensor tests fine, I get a DTC for it.. so i may do a wire overlay from the sensor to the ecm.

 

[DaveMan]

The temp gauge on this car stays down the whole way and doesn't move at all. I don't think the gauge even works. I had the scanner on it and watched the temp and it only comes up so high with the fan on. Then if I unplug the fan it heats up closer to normal, can't remember what the temps were though.