Ribbed heat exchanger and other changes (CA only)

In order to insure that the heater output meets the requirements of extreme climactic zones the heater system has been changed.

  1. The engine heat exchangers are finned
  2. The hot air fan has a two stage switch:
  • First stage (current draw 70 Watt)
  • Second stage (current draw 160 Watt)

The two stage switch for the fan operates automatically. The first stage is limited to stationary heating operation. The second stage is automatically switched on when the engine is started (voltage at regulator swicth D+). This ensures that the current draw is limited during stationary operation.

Service installation into previously produced vehicles is not intended.

Wiring diagram


Cable colors

  • ro: red
  • bl: blue
  • sw: black
  • br: brown
  • ge: yellow
  • ws: white
  • gn: green


  1. Warning lamp
  2. Main switch
  3. Electronic switch
  4. Fuel pump
  5. Temperature sensor
  6. Plug housing
  • 6a. Multi point plug (Temperature switch, relay)
  • 6b. Plug housing (VW 411 wagon)
  • 6c. Plug housing of the combustion air blower cable harness
  1. Cable connector
  2. Ignition coil
  3. Overheating switch
  4. Glow/Spark plug
  5. Angled plug with ignition cable
  6. Thermo switch
  7. Combustion air fan motor
  8. Contact breaker for pump
  9. Contact breaker for ignition
  10. Overheating fuse 8 amp.
  11. Hot air motor
  12. Safety switch
  13. Double relay
  14. Fuse 16 amp.
  15. To terminal 30 of safety switch
  16. Suppression choke
  17. Temperature regulating switch
  18. Time switch
  19. Operational readiness switch
  20. Clock contact
  21. To parking light
  22. To ignition/starter lock
  23. To starter (terminal 30)
  24. To regulator switch
  25. To lighting switch (terminal 30)
  26. Series resistance for hot air fan

The cable which is shown dotted - from the 16 amp. fuse (20) to the plug housing (6b) - belongs to the VW 411 wagon.