A/C System, Electrical Test

A/C system, electrical test

Tools required







- VAG1598/19 test box
- Multimeter (Fluke 83 or equivalent)
- VAG1594 adapter cable set


Connecting VAG1598/19 test box to connector of A/C control head -E87-
- Switch ignition on.
- Open lower instrument panel air vents on left and right and adjust air flow to these instrument panel air vents by operating the buttons on -E87-.
- Switch ignition off.
- Remove side trim panel of center console on passenger side.


CAUTION!
Before disconnecting the battery, determine the correct coding for the anti-theft radio.


- Remove radio.
- Unplug connectors from -E87- and connect VAG1598/19 test box to the wiring harness.


NOTE:
- Press back lock -A- in order to unplug the connectors.
- The assignment of the terminals in the test box is identical to the designations in the wiring diagram.

NOTE: Electrical test changes for model year 2000 vehicles.

List of specified electrical tests

Test 1 - 9:

Test step 1-Temperature sensors

Test 1.1 - 1.5:

Resistance levels of temperature sensors dependent on ambient temperature in kOhms (kilo-Ohms)







Test step 2-Center vent position sensor -G142-

Test 2.1 - 2.2:

Test 2.3 - 2.4:

Test step 3-Fresh air blower -V2- and control module for fresh air blower -J126-

Test 3.1 - 3.4:

Test step 4-Coolant pump -V50- and related valves

Test 4.1 - 4.3:

Test 4.4:

Test 4.5 - 4.6:

Test step 5-Motors in engine compartment

Test 5.1 - 5.2:

Test 5.3 - 5.4:

Test step 6-Motors in passenger compartment

Test 6.1:

Test 6.2:

Test 6.3 - 6.10:

Test step 7-Sensor for compressor speed, low pressure and high pressure switches


NOTE: Test steps 7.1 to 7.4 ( no A/C compressor speed sensor -G111- installed) are not applicable to USA.

Test 7.5:

Test 7.6:

Test step 8-Relay for A/C clutch, actuation of fan

Test 8.1 - 8.2:

Test step 9-Signal for washer/wiper system

Test 9:

Electrical test changes for model year 2000 > vehicles
The following test steps should not be conducted on vehicles with a control head having part number beginning with index letter "M."
- Test step 1.1 (temp sensor -G17- connected to instrument cluster; measured value determined by Can-bus).
- Test step 1.2 (temperature sensor -G56- is installed in the control head).
- Test step 8.1 (activation of relay for solenoid clutch -J44- occurs via connector C terminal 22).
- In addition the voltage supply for terminal 58d is deleted, activation occurs via the Can-bus).

Test step 1 (Voltage supply, Ground, illumination, temperature sensor/sender)

Test 1.10 - 1.12:

Test step 8 (A/C clutch relay -J44-, activating coolant fan -V7-)

Test 8.3:

Test step 9 (Signal for washer-wiper system, connection to windshield defroster control module -J505-)

Test 9.2: