Joe, there is no important difference between the 86-88 and 89-91 rad
fan wiring section of the A/C. Note that the fan wiring pages in the
Bentley have labeling errors for all 3 versions of the larger fan. In
spite of that all wires are shown and you should be able to do this with
minor hair pulling.

The biggest difference in the 2 versions of the A/C wiring itself is for
the 2 Freon pressure switches. The early version has 2 pressure switches
with 2 separate connectors of 2 wires each. The later version has these
combined into a dual pressure switch with 4 wires together.

My understanding was that you were installing some other A/C system and
thus you don't need the VW A/C wiring and can separate the fan wiring
from it by unplugging a 2 wire and a 1 wire connector. The one wire is a
small red/blue stripe and the 2 wire is a large red/black and small
black/yellow.

Mark

Joe Federici wrote:

> Thanks Mark, Is there an easy way to tell which year my AC wiring
> came from. I do have what looks like a complete set of the fan wiring
> but as for the year I'm a bit fuzzy as I'm not the person who pulled
> it out.
>
> JFF
>
> On Nov 28, 2007, at 9:35 PM, Mark Drillock wrote:
>
> Your Syncro already has the "third" fan speed and the relay for it. What
> you are missing is the second speed with it's relay and wiring. The
> diagrams can be confusing about this since the 2 speed version calls
> full speed the 2nd speed and the 3 speed version calls full speed the
> 3rd speed.
>
> Assuming that you pulled the complete fan wiring sub-harness from your
> 86+ A/C donor it should be straight forward to remove the lo/hi version
> fan wiring and install the low/med/hi wiring in it's place. VW made this
> area of the wiring flexible by design so they could use any of 3 fan
> wiring schemes without needing different main harnesses. It is plug and
> play.
>
> You need to unplug the Syncro fan harness illustrated on Bentley 97.200
> and replace it with the A/C fan harness illustrated on 97.141. Dash out
> will be helpful. No wires need be cut. Everything unplugs.
>
> Mark
>
>
>
> Joe Federici wrote:
>
>> Does anyone on the list have experience adding the factory AC wiring
>> to a non-AC van. The only part I'm interested in is the 3rd speed
>> radiator condenser fan and which wire triggers it.
>>
>> I'm going to be using a different condenser and evaporator and just
>> need to wire in the needed relays or wiring to activate the fan and
>> wire it into my system so it comes on with the compressor. I've got
>> all the wiring and relays from a parts van that had AC but I'm having
>> trouble figuring out what I need and don't need. My van is a 1987
>> syncro transporter so I've already got the fan used for the AC vans.
>> Looking at the manual I think all I need is to add the 2nd and 3rd
>> stage fan relays. One looks to be above the fuse panel and other is
>> behind the left fresh air vent but I'm not sure about the trigger
>> wire that activated the 3rd speed.
>>
>> If any knows please pmail me,
>>
>> thanks
>>
>> JFF
>>
>