'02 1.8t - Cooling fan won't come on at all

[16vCorey]

Long story short, I was in line in a drive through, smelled a faint electric/burning smell, then my ac started to get warm. Checked the fan when I got home, and it won't come on at all. Not with the AC, not when it gets hot, not when I jump the switch in the lower radiator hose. If I probe the orange wire coming out of the fan control module with 12v the fans run fine. I have power and ground going to the fan control module. I swapped the fan control module with a used one that was supposedly tested. Still does the exact same thing.

After swapping it to no avail last night, I did a little more digging. Originally I was told that the FCM gets it's signal directly from the ECU, but from what I read last night is there's a relay under the ECM for the fan. I also read a horror story of a melted fuse box and/or wiring going to it, which makes me especially worried since I definitely smelled burnt electronics when it died, so it makes me think it's something in or near the cabin.

Any ideas? Anyone have a wiring diagram for the fan circuit?

[Let it snow]

There are 2 power sources for the module. Red/Green wire and Red/Blue. R/G is powered from a 5 amp fuse #4 in the fuse panel. R/B is powered from a 40 or 60 amp fuse (depending on engine) in the relay carrier above the pedals. The carrier has 4 relays with 4 fuses above and below. On the bottom row it is the third from the left.

[thomastollar]

Hey 16V,

I had this problem too....I am running an 05, so am not exactly sure how similar the wiring is, but inside the cabin there is a 5amp fuse in the driver's side fuse box for fans, and a 60amp fuse under driver's dash. On my car the ECU box seal was bad so I was getting moisture inside the cabin, which fried the 60amp. To check you need to remove the lower dash panel (3 screws - one inside driver's fuse box area, 2 in footwell area, and then some clips below trim. You will then need to unhook footwell light and the ECU port). The 60 amp fuse was just above the clutch brake pedal area....there are a few different fuses down in there, but it should not be a problem to check to see if any are fried.

Also, from what I have read the relays under the ECU cover don't seem to be a problem unless the ECU has been flooded with water.

[16vCorey]

Yeah, all of the issues of the relay near the ECU I read about were from water causing the relay to stick and the fan to run all the time. But I figured if the relay could cause it to run all the time it could also cause them to not work at all if it totally crapped out. But I agree, since I smelled something in the cabin, I'd guess that the 60 amp fuse behind the dash is more likely. I'll check that today.

[16vCorey]

Hey 16V,

I had this problem too....I am running an 05, so am not exactly sure how similar the wiring is, but inside the cabin there is a 5amp fuse in the driver's side fuse box for fans, and a 60amp fuse under driver's dash. On my car the ECU box seal was bad so I was getting moisture inside the cabin, which fried the 60amp. To check you need to remove the lower dash panel (3 screws - one inside driver's fuse box area, 2 in footwell area, and then some clips below trim. You will then need to unhook footwell light and the ECU port). The 60 amp fuse was just above the clutch brake pedal area....there are a few different fuses down in there, but it should not be a problem to check to see if any are fried.

DING DING DING! We have a winner! The fuse was totally melted. The fuse element never actually blew, but one of the spades totally melted off of it. Despite being slightly melted, I dug what was left of the fuse out of the fuse holder and cleaned it out, installed a new fuse and everything seems to work! Thanks!

[16vCorey]