cwiert

I've searched this and found some conflicting info. Are both fans linked together and supposed to come on at the same time?
On my car, I've only ever seen the passenger side fan come on. That said, when the car is off and cool, the passenger side fan is quite free moving (i can spin the fan blades around manually). The driver's side fan moves, but I can't spin it. It's too tight. I'm assuming that this is part of the problem.
BTW - the fuses for both fans are good.

Imo000

yes the both should be coming on at the same time and they both should be free spinning. Check the power at the driver side fan. If it's getting +12V, you fan is done. Also make sure that fan is not rubbing againts somethig either.

cwiert

It will it only get 12V when it's supposed to be running (while the other fan is running, right? (I'm just looking out for my fingers)
Can I simply swap the plug connections on each fan and see if the same passenger side fan comes on?
Last question... is there a way to jump the fans so I don't have to sit and wait for the car to get hot enough to trigger the fans coming on?

Leon Speed

If the fan doesn't spin when not powered the it probably won't spin powered

The fans wil run when the AC button is pressed.

cwiert

ha ha. no, the fan will move/spin, but it's just a little tight. the working one spins much more freely. anyway, yeah, i see your point. either get a new fan, or take that one out and fix whatever is binding it up first, and then see what happens.

BTW - my A/C button doesn't work. lol. another issue for another day.

auzivision

to trigger the fans, jump the temp sensor and depress the 'hood closed' swith on passenger side.

I have an extra fan motor off an 87 you can have for shipping if needed.

My little way of 'passing it forward'.

cwiert

Wow. Thanks Kurt. That's very generous. I'll test the fan tonight to make sure that it is, in fact, the problem. And if so, I will definitely take you up on your offer! Thanks again.
-john

Imo000

Yes you can swap the connector but you will have to un clip the harness a little. However the wiring will reach from the passanger side to the driver side. At least it did for me when I was chasing the same thing a few months ago. And yes, the fan will only have power when the other one is on. If you un plug the temp sensor from the front lower driver's side end tank, the fans will constantly stay on while the ignition is on. I hpe this helps.

Paul Bakker

Hi guys.
I'm dealing with the same problem on my '90 euro S4.
Took the wire from the working fan on passenger side and connected it to the one on the drivers side. It worked so mechanical it's OK.
So now the 1 million question is WHY doesn't the fan on the drivers side spin when AC is pressed ???? I've measured all voltages in the controlling unit in front of car nearby hood closure mechanism and posted them today in a new post.

Any thoughts ???

Thanks, Paul

Imo000

See if the voltage disssapears when the other fsn comes on. That's what happened in my case and the problem was a pair off crappy fuseas that melted but didn't blow. Pull the fuses out and have a really good look at them and the sockets too.

WallyP

Clean the battery terminals - all connections.
Clean the fuses and connections.

Don't just look at them, clean them.

Paul Bakker

I'll do.

Thanks.

Paul Bakker

I did a close inspection. Nothing special, everything looked fine. No burning as a result of extreme heat. I'll start by cleaning the battery connections tomorrow.
Thanks, Paul

Alan

The fans are seperately driven (each has its own driver and fuse) but should always do the same thing - either: both off, both at half speed or both at full speed...

So for a single failed fan if could be a fuse, driver, wiring or motor but given your symptoms I'd say the fan motor seems most likely...

Alan


Alan

dr bob

You can test for voltage at both sides of each fuse with the fuse in place and the fan running (or supposed to be running....). A weak connection at a meted fuseholder may not show up without the load on the circiut. Test voltage to ground, should see battery voltage or very close at both ends of both fuses. A few years ago I threatened to add diagnostic ports to my spare/rebuilt output module. One of these days when I'm at home.