Heated Rear Window -Z1-, Testing

Electrical Testing Of Components Activated By A/C Control Head -E87-

Heated rear window -Z1-, testing

NOTE:
- If a condition exists which disables the heated rear window to be switched on (short circuit in wiring to rear window, open circuit in voltage supply to A/C control head -E87- or the an open top on convertible) the indicator light in the button of the A/C control head -E87- illuminates when pressing the button, and goes out after button has been released, the heated rear window however is not switched on.
- If voltage on terminal "30" measured by the A/C control head -E87- drops below 12.5 volt, the performance of the heated rear window is reduced and the generator load is reduced (the electronic of the A/C control head -E87- reduces the activation from 100% to 90% -10%).

Special tools and equipment
- VAS 5051 Vehicle Diagnostic, Testing and Information System (with current clamp)
- V.A.G 1594 A connector test kit

Test requirement:
All fuses OK:

- Switch ignition off.
- Remove A/C Control Head -E87-.







- Disconnect connectors -D-and -F-from A/C control head -E87- Connect adapter cable V.A.G 1598/12 of test box to disconnected harness connector -D-.
- Connect V.A.G 1598 A test box to V.A.G 1598/12 adapter cable







- Measure voltage between terminal 5 of connector -F- and socket 13 (Ground connection) of test box.
- Specification: approx. battery voltage
- Measure resistance between terminal 6 of connector -F- and socket 13 (Ground connection) of test box.
- Specification: Resistance approx. 0.5 to 1.0 ohm.

NOTE:
- Resistances value smaller than 10. cannot be measured accurately with shop tools, a short circuit in the wiring connection or in the Heated Rear Window -Z1- cannot be detected
- If the resistance value is too large, check and eliminate open circuit in wiring connection to Heated Rear Window -Z1-.







- Connect harness connectors -D- and -F- to A/C control head -E87- (all connectors are now connected to the -E87-).
- Guide wire of connector -F- terminal "6" through current clamp 50 A of VAS 5051/9.
- Select operating mode "Test instrument" on VAS 5051: Current 50 A current clamp on.

NOTE: All harness connectors on A/C control head -E87- must be connected.

- Start engine.
- Switch rear window heating on via A/C control head -E87- (indicator lamp in button lights up).
- Specification: The display on the V.A.G1715 will change from approx. 0 amps to less than 25 amps.
- Wait approx. 12 minutes.
- Specification: The display changes from less than 25 amps to approx. 0 amps (indicator lamp in button goes out).

NOTE:
- The current probe may be influenced by stray current which could cause the display to show a low current reading when rear window heating is switched off.
- The heated rear window stays switched on with outside temperatures up to 0 degrees C until ignition is switched off (heated rear window can be manually switched off anytime). If the temperature increases above 0 degrees C during a driving cycle, the heated rear window will be switched off after the specified operating time -E87-) of approx.: 12 minutes elapsed.
- With outside temperatures greater than 0 degrees C the heated rear window is switched off automatically by the -E87- after the programmed operating time (approximately 12 minutes) has elapsed.