100 Quattro Sedan L5-2309cc 2.3L SOHC (NF) (1989)
A/C Signal: Testing and Inspection
CIS-E III Control Unit Harness Connectors (Pin # Locations)
The relay signals the fuel control unit when the air conditioning is turned on by applying battery voltage to terminal #33 of fuel control unit (parallel
circuit with A/C clutch).
1.
Disconnect harness connector from fuel control unit.
2.
Turn ignition "ON", and check voltage between harness connector terminals #33 and #35 (ground). There should be no voltage present.
2.
Turn A/C on. Compressor clutch should energize and voltage at terminal #33 should change to battery voltage (within 1 volt). If not, check the
relay, listen for a "click" when A/C is turned on and off. If it "clicks" check for open or grounded circuit between fuel control unit terminal #33
and A/C relay terminal 58.