I've been monitoring my coolant temps with a Scangauge this past year and I began noticing in the winter (when driving without A/C), my coolant temp would climb higher than normal. This is expected as the factory fan is set to click on low speed at 215 and high speed at 235 if I remember correctly without any input from the A/C pressure. Well I've sat and watched my coolant temps climb north of 225 before clicking my A/C on so the pressure switch would trigger the low speed fan to turn on and start cooling things down. Where does the fan get it's signal for coolant temp? Obviously, the computer is getting the correct temperature. Both fan speeds work fine with the A/C on. I haven't tried checking if the high speed works without A/C because I just don't want to let it get that hot. Anyone have any ideas?

 

Check out the thread "low speed fan resistor" we need a soloution on page 1 of todays posts. Might be the soloution to your problem. Look on page 5 for Quick inexpensive fix.

 

in short....
your low speed fan isnt working, just your high speed (or A/C one)
your temps are right, i think high speed kicks in at 225 though, but i could be wrong, and low speed kicks in at 215. anyways, your gonna need a new resistor probably or maybe a whole new unit. like stated above, check that thread. itll answer your questions.
-Andrew

 

Are you guys sure? I thought that thread was when the low speed fan isn't working at all. Mine works fine with the A/C. The A/C can kick the fan on either low or high speed depending on system pressure just like the coolant temp. Mine just seems to not be reacting to coolant temp.

 

Is the fan on continously when the AC is on? Or does it cycle on and off?

 

It cycles. It's perfectly normal when the A/C is on.

 

I have the same problem kapps have. I change the resistor and turn on the engine and the fan will not turn on, fuses and relays are fine.

 

Have you let it run long enough to hear the sound change to the high speed fan? If you can hear the fan cycling on and off, it is likely the high speed turning on and off... The low speed is pretty quiet...and runs for a longer period of time. Maybe there is a more indepth way to check for fan failure, and I am sure the dealer would troublesoot it for $175 per hour....
If the fan in cycling on every 1 minute or so, this is typical of how it acts when the low speed has failed.......the low speed fan is not very noticable when on.
If everything else checks out, Since you have an 02', perhaps the relay (located on the fan on the 02's is stickey....or the failure mode is somehow different. Just a guess, but it sounds better than saying the ECU or BCM is toast....

 

Zippy, it cycles between low speed and high speed. It's like the fan is working perfectly when running off the pressure switch in the A/C but doesn't work when only reading coolant temperature.

 

Well I was able to take a closer look at it and it is indeed the low speed fan issue that everyone's having. It's the high speed fan that's cycling on and off with no low speed. I could have swore the high speed made more noise than it's currently making. Thanks all for the troubleshooting. Looking at Rock Auto and go-part.com for replacements. Any recommendations which one to get?

 

The TYC one is very popular....I installed one on mine....seemed to be very well built. Many folks on this site have bought/installed it.

 

I seem to have this same problem. However, on my car I noticed white crust and what seemed like over-spray around the overflow bottle several times after wiping it clean (I monitored the coolant and it is staying at level) which is what began my questioning. I then read how to pull up the ECT on the odometer display and my car will go above 103 Celsius and no low fan kicks in with or without ac. I then notice that when it hits 113 Celsius the high fan kicks on and when the ac is on the high fan stays on and does not stop. I checked the relays so it leads me to believe that the fan is no good. I ordered a TYC For $80 and will be taking a shot as I am 99% sure this is the problem!