After Run Fan (was: I've got a wire loose)

[David.Ullrich at ferguson.com]

Oh, one other thing, does it matter which way the sensor is hooked up. There is no apparent difference in the wires/terminals and the PO could have hooked it up backwards if he fooled with it...

Dave

-----Original Message-----
From: David Ullrich - 0018 HQ
Sent: Thursday, June 13, 2002 11:43 AM
To: human747 at attbi.com
Cc: quattro at audifans.com
Subject: After Run Fan (was: I've got a wire loose)


OK, the fan DOES come on if the wires are shorted together. So, do I even bother heating up the sensor with a lighter/torch? Or is it safe to assume it is bad? Or could it be that I've never gotten it hot enough to kick in? It was in the mid 90s with high humidity yesterday during my drive home which was sustained highway 55-80 MPH for 45 minutes with the AC on full blast the whole way. I would assume that should have been enough to kick it in, right?

Dave

Too Many Toys:
2002 VW Jetta GLS 1.8T Tiptronic
1993 RX-7 R1
1987.5 Audi Coupe GT "Special Build" 2.3 - Anthracite Black
1985 Chevy Impala SS
Former:
1981 Audi 4000 5+5
1982 Audi Coupe
1988 Audi 90 Quattro
1998 VW Passat GLS 1.8T



-----Original Message-----
From: Huw Powell [mailto:human747 at attbi.com]
Sent: Wednesday, June 12, 2002 5:43 PM
To: David Ullrich - 0018 HQ
Cc: quattro at audifans.com
Subject: Re: I've got a wire loose



> That's pretty much my experience with my 87.5 CGT. Three wire fan, 2 speeds. Low speed most of the time, high speed when REALLY hot or when AC pressures build up high. No sign of an after-run feature so far, but I don't drive the car hard during the last few minutes of a trip so it may not be hot enough to kick in when I park it. Do you think I should have an after-run? Any thoughts on what to look at?

you do have the system, whether it works or not is another question.

find the bracket on the back of the head, mounted with two cam cover
bolts.

carefully pull off it two wires.  just after turning off the engine,
short them to each other.  if the fan runs, the relay and wiring are
good.

now, if you want to check the sensor, here is the silly, "do not do this
at home, kids" method.

connect the wires again.  carefully heat up the bracket with a propane
torch, being sure not to heat *anything else* up, like nearby hoses or
wires.  the fan will come on after a minute or two of this if the sender
is good as well as the rest of the system.

these normally aspirated cars seldom seem to generate the underhood
temps required to activate this system, unlike our fire breathing turbo
friends.

As a side note, I rigged my '82 coupe (no afterrun system) radiator fan
system to run on the battery instead of ignition, so the regular
one-speed fan runs after shut-down based on coolant temp, not underhood
temp.  It will often kick in just as I turn off the key, but only run
for 30-60 seconds.  But that engine usually gets right foot punishment
whenever I choose to drive it.

--
Huw Powell

http://www.humanspeakers.com/

http://www.humanthoughts.org/