[Vwdiesel] 91 Eco Fan Troubles

[Will Taygan]

So I've been poring over the Bentley wiring diagrams for a few hours and
it's starting to make sense, I think.  But I still have to find the
wires to test.

----------

Issue:

** WHERE IS THE S23 FUSE FROM THE BATTERY TO THE A/C RELAY? **

The fuse block goes to 22, and Bentley shows the S23 floating free on a
red wire from the battery.

I guess tomorrow I'll pull the A/C relay and just test the incoming
connection.  Too late tonight.  And even if I figure out my preventative
strategy, should I go with a new radiator fan anyway?  Something else
making it overheat?  Fan not running makes an easy target - but it's
running now.  I guess I'll drive it a week and see, although I was
supposed to take this one on a road trip Weds..

----------

Background:

91 ecodiesel usually pegs at the middle tick. Sure, a tiny waver up on
the hills, maybe 1/2 way to the third tick on mountain passes.  

Driving this last week it hit the third tick on the flats on the
highway.  Popped the hood, radiator fan was smoking, not spinning.  I
gave it a whirl and things started up.  

Halfway back down to the second tick the fan stopped.  I figured the
thermoswitch kicked off.

A/C compressor is disconnected, as the A/C hasn't worked since I got the
car 2 years ago (just renewed registration last month).

Previously I would preventively turn on the radiator fan on the uphills
by flipping the A/C "on" with the dash switch.  Fan runs, compressor
stays off, everyone's happy.

Now, I flip the A/C "on" and there's just the click at the relay.  No
fan.  

The S19(?) 30amp fuse under the dash is good.  I can get the fan to run
at high and low speeds by jumpering the thermoswitch harness.  Sounds
noisy but runs.

S6 A/C control and blower fuse is good - blower works.

----------------

The Nitty Gritty:

I'm trying to find and test the wire from the A/C switch that turns on
the fan.

In Bentley p255 is for the German made 1989 Jettas, but it shows an
"After-run" relay, which I don't think I have, at least I can't find
where one would be on the cylinder head.

p257 is the 90-92 Canadian Jettas, hmmm.  Mine us definitely US, but
these don't have the after-run relay.

The point may be moot, as the diagrams are fairly similar.

So the A/C pressure switch is a safety cutoff?  It appears to have two
parts. One is normally closed, allowing the A/C thermostat to turn on
the A/C compressor.  The other part is normally open, but if closed
kicks the fan from low speed to high speed?

And the main (J32) A/C relay turns on two parts as well, the A/C
thermostat (and pressure switch - compressor circuit) and the fan (N/2)
circuit.

Too many R/W wires!#$%!

Gotta find the R/W wire from the N/2 to T2l to K20 circuit.  That would
tell me if the fuse is good and if the relay were good. Anyone done this
before and remember?

Thanks,

Will.