Two curious things about AAN wiring...

[s2_wot]

So, is there any way to test the AAN after run cooling system that it works? I have a new pump and 105C switch, but I'm not sure if the system works at all, havn't heard the pump go on at any point.

I've read that a lot of owners in the US install a fuse between the wires that normally connect to the temp sender. This means that if the relay is in good working order the fan and pump will run for 10 minutes after you stop the car no matter what the conditions. You could try that to check that the relay and pump and fan are working.

[gerardiro]

i test the after run cooling system by making a short circuit between the after run switch pins

[S2central.net]

I would say that since the AAN was developed before the ABY or ADU, that the curious differences with the AAN are really ABY/ADU differences.

I always thought that your (Paul's) suggestion that the after-run pump (and the fans) run on AAN start up was wrong but since it wasn't (and isn't) a big deal, I let it slide.

The AAN after-run pump is only triggered by the after-run switch. Then it stays on for 10 minutes (via the 324 relay) or until the temp drops down enough. There is no need for the pre-run operation.

http://forums.quattroworld.com/s4s6/msgs/21503.phtml

Yeh - I always assumed that AAN would have been same in this regard... but it is now clear that is not the case - it is a superior upgrade added to the ABY & ADU motors. hehe

[Thuppu]

Ok, thanks guys. Thats really simple to test.

[DJones]

My Ur has the AAN loom fitted and the after run pump primes when the ignition is switched on... wired it as per the factory diagram..

Darren.

[UrS4boy]

My Ur has the AAN loom fitted and the after run pump primes when the ignition is switched on... wired it as per the factory diagram..Darren

Any idea of the build date of the car that was the donor for your AAN and ECU? Could be early C4 UrS4s didn't get that feature but by the later UrS6s that feature had been integrated into the ECU.

Or not.

[Ian Simmonds]

My Ur has the AAN loom fitted and the after run pump primes when the ignition is switched on... wired it as per the factory diagram..

Darren.

Ditto, ours is the same on the RallyRep... Basically the RallyRep is an Audi S6 in a CQ shell rather than an AAN in a CQ, if you get my drift. Even got functioning Vag-com.

[DJones]

Any idea of the build date of the car that was the donor for your AAN and ECU? Could be early C4 UrS4s didn't get that feature but by the later UrS6s that feature had been integrated into the ECU.

Or not.

It was a 94 urs4 none immobiliser car..

[S2central.net]

The other possibility is that the NON integration with ECU was a USA thing... I am going by US Bentley schematics here which seems to line up with URS4boy experience and the N.Am crew...... but here is a couple UK folk with a different experience than Shane... will test for myself on a local AAN this week.

[Ian Simmonds]

It was a 94 urs4 none immobiliser car..

ours was a 96 UrS6 immobiliser car..

[s2_wot]

The other possibility is that the NON integration with ECU was a USA thing... I am going by US Bentley schematics here which seems to line up with URS4boy experience and the N.Am crew...... but here is a couple UK folk with a different experience than Shane... will test for myself on a local AAN this week.

I'm happy to go back to living with a glitch