1995 90 Radiator Fan Speeds Not Working [Archive] - Audi Forums

: 1995 90 Radiator Fan Speeds Not Working

07-12-2011, 08:29 AM
*First, let me say hi, and thanks for any help. I am a poor college kid and I try to do all my own work. I keep it clean and do all the routine maintence that I can do myself. I'm keeping the car stock, as purchased, no mods like exhaust or spoilers or silly **** like that for a 170hp FWD car. I just need it to be reliable and get me where I'm going, and I'm slowly but surely eliminating the bugs I bought it with! I need some help sometimes, though..

I'm ew to the forum but I've had the car 3 years. Haunting old posts didn't show anything quite like what I'm looking for.

The problem is that I believe I am supposed to have multiple radiator fan speeds, but as it is I only have one- full tilt when the engine is really hot. The temp will climb to a point, kick it on, cool off, repeat. The fusebox shows I think two empty relay spots and the fuse panel mentions "speed 1" and "speed 2".

Other notable things: my AC doesn't hold pressure and so doesn't work. I don't care, windows are fine by me. But might that cause it to not kick on the slower speed? I know they're the same fans. When I push the AC button a slower speed comes on and will help a lot to hold a steady medium temp on a warm day. I am not afraid to do this, but I don't want to burn up my AC compressor or something if it is trying to kick it on.

What should I look for to be wrong...? Relay? Wiring? Did this car in reality just not have multiple speeds? (Could I get a dummy pully to put in place of the AC compressor?) I'm running back to the stealership today to return a gallon of untouched G12 and I'll ask them too.

I really appreciate the help!

07-13-2011, 04:58 AM
bmw gut here, bentley book should have wireing ,i have not gotten thru my c/d yet (paper book better) ! no longer in print !
BUT, if a/c is out, pull leed from a/c comp (just to make sure),
my 95 - 90, seems to have 1 speed - high to cool rad
2.8 alum eng, dont let it get hot ! heads will blow, i'd use a/c to keep cool in traffic - just to make sure

07-13-2011, 07:18 PM
Hi! Agreed with roy, diagrams would help.

On my audi 100 I had N39 Coolant F C (Fan Control) Series Resistance board cracked, so previous owner connected high speed directly. You may also have 2 contact temp sender instead of three. You should really get the diagram and check if it is supposed to be 2 speed. If yes and it turns on late, check the temp sender on the bottom of the radiator.

07-14-2011, 08:04 AM
I spoke with the mechanic about this when I went in to buy some G12 and drain/flush/replace the coolant.

I asked if I was supposed to have two radiator speeds and a relay for the first which I found seemed like it would be the A/C "on" speed. He agreed that it would have two speeds but often the relay blew for speed 1 (the intermediate speed) leaving only the second speed. I priced a relay-$25. Do-able. I'm going to try and kick off the A/C compressor like you said. Hopefully it won't fault that circuit and I can still use the fan on it. I do hear the sound of a compressor when I use it so I'm still a little timid of over using it.

Funny note- when I went to do the coolant I found the drain plug quickly, got it out and... Nothing! What the Hell?! I poked around with a screw driver and got some sandy-looking stuff out, but no water at all. Went up to the top and put as much pressure as I could with my mouth on the tank and some started dripping. Put my hand over the tank and using an air compressor nozzle and my hand over the opening blew on it and it started GUSHING like it should. Capped it, filled with water, circulated as best I could, drained, filled, circulated, drained, then put new 50/50 G12 and tap water in. It took not quite two total gallons. Which is weird because the book says its 2.9 gal. I'm not worried about it. It's not losing fluid and it holds temp and blows hot air. That was quite a diversion from the subject though!

07-26-2011, 12:59 AM
Wow sounds like someone put that stop leak crap in the cooling system which on these older audi's you never ever do. It comlpetely gums up the entire system and turns everything to sand or concrete. As to your rad speed problem...definatley a relay problem.

07-26-2011, 05:35 PM
As with my 1994 A90CS, the only time my fans go on is when the compressor is on. The relays I have;
- "Relay for air-condition"
- "Radiator fan relay"
- "Relay for radiator fan (speed 1)"

I DO NOT have;
- "Radiator fan delay"

07-26-2011, 07:51 PM
I think I have those too but not the Speed 1.

My mechanic said the Speed 1 went bad a lot and often was just left out because the hardwire prevents it from overheating. So I will probably just watch it manually with the AC compressor fan.