monkeybird747

Hello all, I'm moving this post from the 2.7t area in hope of some responses. Maybe this will help someone else out too.

2002 Allroad 2.7t

Symptoms:

1. A/C started getting really warm while at idle. Ice cold when driving.
2. Started noticing the temp creeping toward 3/4 hot when idling for extended periods.
3. Haven't seen either electric cooling fan come on by itself (in front of radiator and behind on passenger side.
4. Hearing a lot of periodic hissing when the A/C cuts in and out at idle. About every minute or so (normal?). The hissing coincides with the a/c getting warmer.

What I tried so far:

Had A/C charged. They put in about 2 ounces. I didn't notice any difference.

Took to the local Audi indy shop. They said bad fan control unit, which coincided with what I had read on this site. They bench-tested the electric fans and both worked with direct power. They wanted $600 to repair, so I thought I would take a shot at it. Ordered a replacement from URO Parts (mistake?).

Installation wasn't terrible. Managed to get both nuts back on and the wires back in the factory routing. However, the electric fans still don't come on. Even with A/C full cold, no econ switch, Oil temp around 225, and coolant temp 3/4 scale hot. Turning the heater on brought the temp back down. Oddly enough, even with the heater full hot, I was still hearing what sounded like the a/c compressor kick on and off, with the associated hissing sound. I also noticed my climate control tries to automatically control the fan speed when I adjust the temp, even though the AUTO mode in not selected. Not sure if this is normal for this car, or if my climate control module is going bad.

I changed the fan control switch (blue) and coolant temp sensor (green). No change.

I pulled the fan connections next to the washer reservoir and applied 12v to the two different two-pin connectors for the fans. The reddish-brown one for the fan in front of the radiator, and the black one for the passenger side fan. The fans came on. I had to give the one in front of the radiator a gentle nudge but it came on (maybe because I was using a pretty small jumper wire made from speaker wire?).

I used a multimeter and checked the other side of the connection coming from the fan control module, and only have around 9.8 volts d/c or so to each fan. I don't know if this is normal, or if I should have a full 12 volts. I read something about pulsing/modulated power yadda yadda yadda from the FCM, so I'm not sure what exactly I should read coming out of the FCM. I was expecting 12 volts though.

So, did i get a bad replacement from URO Parts, or is there something else I'm missing? Also, I assumed the fans not working had something to do with the A/C getting warm at idle, but could I be dealing with two separate problems?

I could use some additional insight. The only thing I can think to do is try a different FCM. I hate to drop the $215 for a new factory one, but I probably should have. Then I would be second-guessing the status of the replacement.


Cheers!

bertrenolds

So basically from what I have read the uro aftermarket controllers are crap and lots of people have had issues with them not working. Maybe there is a version that is aftermarket that does work but if I remember right we need the real oem one I think.

monkeybird747

Thanks Bert, I have an OEM one on the way. I'll post the results. Someone else mentioned the air quality sensor near the cabin filter has a say in the A/C operation. Another mention a bad positive or ground connection, since I'm only getting 9.8 volts out of the fan control module. Not sure how to test the quality of the positive and ground connection though.

cameltrophyallroad

Mine does the same thing, I had one bad fan, replaced it now it works but if the car is in 80 degree stop and go traffic with A/C on the temp sky rockets to 3/4, i changed the coolant temp sensor, no difference. I then changed the inside electric fan, and have checked it when its hot to confirm it does run. Wondering if this is thermostat related, it is for sure the A/C that sends it higher than normal. car #2 I've had for ten years does not do that but i rarely have that car in hot summer traffic so not sure. Keep us posted if you find an issue.
Good Luck

monkeybird747

Does your AUX passenger-side fan ever run with the A/C on? From what I've found during my research that fan should run anytime the A/C is on (and no ECON button selected), and that this could cause A/C related high coolant temps. I'm sure many other issues could contribute also. I'm changing the FCM module with the new OEM one next week, and I'll update after that.

cameltrophyallroad

Yes, it does run when the AC is on, so i thought it was good to go but even with it running the AC in hot temps will push the gauge way higher than normal. will look fwd to what you find out.

bertrenolds

I am beginning to wonder if the radiators just go bad on these cars, I flushed my whole system and went to normal green coolant and its seems like the hottest it gets now is 225-245, i have not hit 250 on my oil temps yet and my coolant temp needle is always straight up and down. I did have overheating problems but electric my coolant fan was bad and my oil temps hit over 250 and then my temp needle went thru the roof. I guess there is supposed to be a hi/low setting for these fans but even when I had the car running and the correct pins jumped it only seemed like hi worked or there was one speed so I was still unsure. I have not had an over heat yet, fingers crossed since I replaced my down pipes with piggy pipes, replaced o2 sensors, flushed coolant, replaced fan. Just replaced my egt sensors and a cam sensor in back so hopefully I am good till I replace the radiator and do the timing belt and cam seals in a month or 2. I swear to god these cars are cursed after they hit 150k, unless you can fix cars dont own one!!!!!

PetrolBear

"I also noticed my climate control tries to automatically control the fan speed when I adjust the temp, even though the AUTO mode in not selected. Not sure if this is normal for this car, or if my climate control module is going bad."
No, it is normal, it tries to reach the desired inside temp.


Beware, your car is overheating if the coolant temp excides the " 12'o clock " (middle position) in the instrument cluster. AC operation always lifts the coolant temp so perfect heat managment is essential with AC.
Download SSP198 from the net. There you will perfectly see how the heat managment works. The fan control unit drives the fans with and without AC and depending the temperatures. However it need to receive reliable good signals from the coolant temp, etc.

You need to install an original control module, not an aftermarket type - it is completely unsure how it works. Signal senders also must be perfect. Check for wirinng, too - car may suffered from some genious previous owners/indys.

This must be enough.
If not, you will need to change the radiator. I had to do this too..but, with a new and reliably clean radiator having the original appr 44mm width (not 35mm aftermarket crap / TDI version !!) plus, with the working fans you will be definitely always OK regarding the engine temps.

monkeybird747

Thanks for all the responses. Here is my post form another forum explaining whats going on now:

Ok, so I think I have everything fixed. Or it's at least broken in a way that is working for me. The problem? I'm not exactly sure what fixed my fans.

So on the advice of others in regards to crummy chinese URO parts, I re-replaced my fan control module with a new OEM made in Hungary. I'm getting pretty good at replacing these FCMs, so if anyone wants any tips I'm your guy! After it was replaced I started the car, turned on the A/C to max cold, made sure the econ button was off, and poof! Nothing. Still no electric fans turning. Not the passenger side one, and not the one in front of the radiator (and the car was hot). I was seriously bummed and ready to take it to a mechanic. I buttoned everything up and moved on to replacing my heater core, which turned out to only be about a 30 minute job. In the process of reinstalling the heater core I made a little nick in one or two of the wires in the giant bundle that runs next to the heater core and behind the center part of the dash. There was a small spark, and many expletives. I finished the heater core install, taped up the bundle, and pulled every single fuse out of the driver's side fuse box and visually inspected them. I had a 10a fuse blown for brake lights (#13 i think). I replaced it and chocked it up to my careless sparking during the heater core install. I started the car and turned the heat up to full blast and began bleeding the new heater core. When I was finished I turned everything back to cool and voila! Both electric fans came on and were going gangbusters. I let the car idle for a really long time and I got no overheating, the compressor didn't kick in and out every few seconds, and the a/c blew cold the entire time. This was at 90+ degrees ambient in central Texas today.

Oddly enough, now none of my driver's door lights work. No puddle light, or red entry light, or driver's footwell light. I checked all fuses. I'm baffled. They worked before I removed the kick panel. Maybe I forgot to plug something back in?

So, its still too early to tell if the fans will work correctly from here on out. However, I have a few possible reasons things may have started working, and have listed them in descending order of probability:

1. I pulled every single fuse in the fuse box during my visual inspection. Maybe, without knowing, I jogged a computer or relay or controller or something by pulling its fuse.
2. While I had the kick panel removed from beneath the steering wheel I pushed and wiggled the various relays that were within reach to make sure everything was seated correctly. I know that there is more than one relay down there in the 8-fold and 13-fold panels that has something to do with cooling fans. Maybe I wiggled the correct one?
3. When I shorted the wire whilst installing the heater core, I randomly shorted my driver's door lights to the aux cooling fans, and the door light circuit is now powering my cooling fans in perpetuity, or until something melts.
4. I actually didn't fix anything, but rather I had a heatstroke underneath the car and am actually still lying there, 10mm wrench in-hand, waiting for someone to wonder where I am. In which case I'm not actually writing this, and you're not actually reading this.
5. Plasma ***** from a nearby thunderstorm jolted the fans to life.
6. The swears I uttered were in the proper sequence so as to conjure an ancient spell, thus exorcising the electrical demons plaguing my allroad.
7. Spiderman fixed it (everybody gets one).
8. Something to do with Chemtrails.
9. Microscopic thermite detonations set by the government.
10. I finally got the 1.21 gigawatts I needed to by harnessing the power of lighting and channeling it to the allroad through a piece of clothesline and the roof-mounted whip antenna.

Now I just need to figure out whats wrong with my driver's door lights. When I open the drivers door nothing comes on. Not even the overhead dome lights. But, when I open the passenger door the proper lights come on, including the dome lights. Door switch?

PetrolBear

Well done!
"Now I just need to figure out whats wrong with my driver's door lights. When I open the drivers door nothing comes on. Not even the overhead dome lights. But, when I open the passenger door the proper lights come on, including the dome lights. Door switch? "
I have the same problem, door switch. Might be a coincidence. BTW I will not repair mine, does not worth the expense to me (exchange of entire door module including 3 (4?) switches and lock mechanism.