MKIII A/C - Cooling Fan -  Data Page;

System fill spec: 28 oz of R134a - 3.9 oz (total) of PAG based oil.

Typical pressures should be 205 Psi high side, 17 Psi low side.

Common failures:
No A/C at all = Low R134a charge, charge and test for leaks.
A/C works for a short time, and then shuts off once car warms up = Replace Cut-Out Switch on cooling flange or jump it.
Water leaks on floor = Look here

I get my A/C hardware from here - or - 
To test or bypass switches, use schematic below and simply jump connector with a paperclip.
The A/C ambient temp switch is located here in the raintray and was the source of much confusion!


Well, here's a fast test. The Fan should Should have these colored wires:

Brown (ground)
Red/White (low)
Red/Gray (high)

Locate the fan sensor (drivers side, near headlight, in rad..) its a 3 wire sensor.
It should have these wires:

Red +12V from fuse 19, 30A under dash
Red/White (low speed trigger)
Red/Yellow (high speed trigger)

Check All fuses under dash. 19, 6 and 4 are key as well as a brass colored bar on the coolant module.
Anyhow. On the fan sensor, unplug it, and jump with a paper clip:

RED to Red/White (fan should come on low speed)

Unplug it. and then;

RED to Red/Yellow. (fan should work on high speed)



IF the fan DOES NOT come on jump power TO THE FAN.

IF THE FAN RUNS when jumped directly to power:

Replace FCM.

If fan does not work replace fan motor.--

If the coolant light on the dash is bad;

Unplug 2 pin connector from coolant bubble.

NOTE:Inspect end of plug for "white crust" or signs of coolant.

If coolant is seen at the end of the plug either on the harness, or the coolant bubble. Replace the bubble.

Start car.

Coolant light SHOULD NOT BLINK while car is running.

If coolant light blinks;

wires SHORTED in coolant wire harness

bad cluster

Turn car off.

Jump wires on plug (harness side-still unplugged) with a paper clip.

Start car.

Coolant light should flash within 10 seconds.

If coolant light DOES NOT flash, check;

broken wires in coolant sensor wire harness

cluster plug unseated

bad cluster

Unplug sensor (paper clip).

Light will still flash.

Turn car off.


Insert coolant bubble plug.

Here's a schematic and locations of the components:

This is from a 1996 Jetta.  Note Cabrio and VR6 the same as 2.0's - all years.  That being said part "1" below (fresh air filter) was never placed into the MKIII production line.

Here is another link, this is for a 93 Passat, but the controls are the same as a MKIII.,