AUX Auxiliary Fan not working but its not the FAN!

[David.X5]

With the fan plugged in (and secure, they will tear you up) try forcing it on by turn the AC to max. Also pay attention to the fan when you unlock the car and turn the key on - fan should run for a few seconds in self test.

From these two anecdotes I suspect there is some sort of time out if you run the car with the fan unplugged. Don't know what exactly will reset it, but it seems to reset.

The fan has some fancy speed control electronics. If you have burned it out, it will smell nasty. Some have even started car fires when they burned out. Nothing subtle...

[upallnight]

If you think the fan is bad, have the car scanned. A bad fan will show up in the DME module. You can also check the 50 amp fuse in the fuse box. If it is blown, you fan is shorting out.

[4b1z]

I was able to finally get the fan to kick on by disconnecting the AC pressure switch. Once I did this the fan started up and started spinning at max speed. Unfortunately I did not try this with the old fan to see if it was truly bad but the fact that it was not turning on when the car reached high temp leading the car to almost overheat tells me that it was bad.

The new fan kicks on now only when the car reaches high temp so at least I will not have overheating issues. It still does not kick on when the AC is turned on and the AC compressor clutch is also not engaging which tells me either the AC pressure is possibly to high (from the aux fan not kicking on) or to low or the worst case the compressor is bad.

Thanks for your responses so far. I am going to try and check the high and low pressure today and see if the system needs a refill.

Cheers

[richardb]

Sounds like an interesting problem. Usually the pressure in the system goes really high because of the lack of the fan working. That can damage the AC compressor, certainly puts strain on the whole system. Did you install a new fan?

I made this DIY for the fan installation, in case anyone is curious about what it takes to replace theirs.

https://www.youtube.com/watch?v=N_K0KPHsteA

[4b1z]

The pressure measured at 105 psi on the low side but of course the clutch is not engaging on the compressor. I checked for voltage at the compressor and it is getting the usual intermittent 13 volts or so. Going to purchase a replacement clutch off ebay for $55 and hopefully I wont have to swap the compressor out.

Thanks for the DYI vid richardb, I watched all of the ones I could find before changing my Aux fan. One thing that was not very clear in any I watched was how to pull out the left and right side of the bumper cover. I ended up figuring out to just pull it straight out from the sides first. I still ended up snapping one of the guides but it went back on fine.

[richardb]

Originally Posted by 4b1z

The pressure measured at 105 psi on the low side but of course the clutch is not engaging on the compressor. I checked for voltage at the compressor and it is getting the usual intermittent 13 volts or so. Going to purchase a replacement clutch off ebay for $55 and hopefully I wont have to swap the compressor out.

Thanks for the DYI vid richardb, I watched all of the ones I could find before changing my Aux fan. One thing that was not very clear in any I watched was how to pull out the left and right side of the bumper cover. I ended up figuring out to just pull it straight out from the sides first. I still ended up snapping one of the guides but it went back on fine.

I actually split this DIY into two parts, here's the first part showing the bumper removal:

https://www.youtube.com/watch?v=QkPxUSSa0L8

[4b1z]

Happy to report that after I was finally able to remove the clutch, pulley and coil that the coil was fried from an exposed positive wire to it. It was a pain in the ass to remove still on the car but after removing the bolts to the compressor and moving it back to get a better angle to remove the snap rings I was able to swap it out. I used PBS Blaster catalyst penetrating spray on the pulley and let it sit overnight and it came off easily the next morning.

The clutch is now engaging, aux fan is turning on and AC is blowing cold as can be. I was sure to protect the positive wire from getting near the pulley as I think that is what exposed the wire and shorted the coil before.

Next job is valve cover gasket and Vanos seals to get rid of this darn oil leak.