Checking Operating Switch

CHECKING OPERATING SWITCH

Note: With operating switch removed and all connections made, use a voltmeter to test voltages at the 15- pole plug.

1. Switch on ignition.

2. Connect voltmeter to terminal 1 (plus) and terminal 4 (minus).
Air-distribution slide at bottom and bottom/top.
Reading: Battery voltage.

3. Connect voltmeter to terminal 2 and terminal 4.
Air-distribution slide at off, center and bottom.
Reading: Battery voltage

4. Connect voltmeter to terminal 3 and terminal 4.
Switch on position lights.
Reading: Battery voltage.

5. Connect voltmeter to terminal 5 and terminal 4.
Air-distribution slide at centre, bottom, bottom/top, top and defrost.
Reading: Battery voltage.

If no voltage is registered, check whether fresh-air blower relay switches. If the fresh-air blower relay does not switch, test the signal at terminal 86. Connect voltmeter to terminal 15 and terminal 4 of operating switch. Air-distribution slide at the same positions.
Reading: Battery voltage.

6. Connect voltmeter to terminal 7 and terminal 4.
Air-distribution slide at center, bottom, bottom/top and defrost.
Switch on auxiliary air conditioner.
Reading: Battery voltage

If no voltage is registered, check air-conditioner switch.

7. Connect voltmeter to terminal 6 and terminal 4.
Air-distribution slide at center, bottom, bottom/top and top.
Switch on auxiliary air conditioner.
Reading: Battery voltage.

8. Connect voltmeter to terminal 8 and terminal 4.
Air-distribution slide to center, bottom, bottom/top and top.
Temperature regulator slide at 18.
Reading: Battery voltage

Move temperature regulator slide to 27. The setting motor moves toward heating. At 10%, the voltage in interrupted.

9. Connect voltmeter to terminal 9 and terminal 4.
Air-distribution slide at off.
Reading: Battery voltage

10. Leave voltmeter connected to terminal 9 and terminal 4.
Air-distribution slide at center, bottom, bottom/top and top.
Switch on air conditioner.
Temperature regulator slide at 18.
Display: Battery voltage.

Set temperature regulator slide to 27. The setting motor moves toward heating. Voltage is interrupted at 10%.

11. Connect voltmeter to terminal 10 and terminal 4.
Reading: Battery voltage

12. Connect voltmeter to terminal 11 and terminal 4.
Air-distribution slide at defrost.
Reading: Battery voltage

The fresh-air blower must run at top speed. If not, check defrost relay or fresh-air blower.

13. Connect voltmeter to terminal 12 and terminal 4.
Air-distribution slide at center, bottom, bottom/top and top.
Temperature regulator slide at 18.
Reading: Battery voltage

Move temperature regulator slide to 27. The setting motor moves toward heating. Voltage is interrupted at 20%.

14. Connect voltmeter to terminal 15 and terminal 4.
Air-distribution slide at center, bottom, bottom/top, top and defrost.
Reading: Battery voltage

15. Disconnect cable plug.
Connect ohmmeter to terminal 13 and terminal 14.
Move temperature regulator slide to 18.
Reading: approx. 750 ± 100 Ohm

Move temperature regulator slide to 30.
Reading: approx. 1750 ± 100 Ohm

Note:
- The resistance must change by approx. 1000 Ohm.
- If the values at terminals 1, 2, 6, 9, 11, 12, 13, 14 and 15 are not attained, the operating switch is defective and must be replaced.
- If the values are not attained at the other terminals, check the wiring using the circuit diagram.