I’m having a bit of a problem. The cooling fans are not getting power.
I know they work because I ran a jumper wire from the battery.

They do not come on when the water gets too hot (believe me I know!) or when I turn the AC on.

So I’m down to three possible causes.
Either both relays (J 26 and J135) are bad, the 40A fuse ( S 42) is blown, or there is a wiring problem.

My current problem is finding the damn 40A fuse #S 42.

I looked in the relay/fuse box under the hood, in the fuse panel in the side of the dash, and behind the knee panel on the driver’s side, but can’t find it.

Does anyone know where Audi hid the fuse?
Bentley doesn’t tell me where it is.

 

Well you can test those relays by jumping the pins 85 and 86 and see if you hear the relay click. If they don't click the coil in the relay is broken.
I believe that fuse your looking for is parked right next to the ECM.

 

Thanks auditec79 as usual you have the good answers.

I found the fuse - it's Ok
and the two relays click when jumpered - they are OK

I jumpered the radiator thermal switch and the fans worked. Could get both high and low speeds so the wiring thru the fuse and relays are OK. But the A/C would not make the fans go on. I'm guessing that there are two problems - The obvious - radiator thermal switch and something in the A/C control circuit - maybe Fuse S13.

I've changed the theraml switch and I'm off looking for the 25A fuse S13 that feeds the A36 wire connection (75a) in the instrument pannel wiring harness. That's what Bently says! LOL

 

Update Thermal switch fixed the problem