VW T4 Air Conditioning / Heat Units comparison LED change / repair & disassembly

Rear fresh air blower front and rear with additional heat exchanger - Facelift model year 1999

• type 7D1 819 045 L (7D1819045 L)
• Frame 7D1 819 075 D (7D1819075D)
• Upper Heat/AIR Control 7D1 919 383 (7D1919383)

Wiring schema

Components

• E9 – Fresh air blower switch
• E20 – Switches and instruments - lighting control
• E159 – Fresh air and air recirculation switch
• J485 – Auxiliary heater operation relay, control number
  (106)
• N24 - Fresh Air Blower Series Resistance with Fuse
• N63 - Fresh Air/Recirculating Flap Two-Way Valve
• S97 – Fresh air blower fuse 1
• S98 – Fresh air blower fuse 2
• Air conditioner relay (140) position 1 (top left)
• L16 - Fresh Air Control Lever Light
• V2 - Fresh Air Blower

• E100 – Warm air blower switch
• J14 – Warm air blower relay, control number (53), in
  centre behind dash panel
• J162 – Heater control unit, control number (152), in
  centre behind dash panel
• N72 – Series resistance for warm air blower
• N82 – Coolant cut-off valve
• S51 – Additional heat exchange fuse, under relay plate

Wiring schema

Rear fresh air blower front and rear with additional heat exchanger - Model year 1997

• type 7D1 819 045 A (7D1819045A)
• frame 7D1 819 075 C (7D1819075C)

My Disassembly video

Wiring schema

Components

Fresh air blower

• E9 – Fresh air blower switch
• E20 – Switches and instruments - lighting control
• N24 – Fresh air blower with overheating fuse series
  resistor
• V2 – Fresh air blower

Fresh air and air recirculation switch

• E159 – Fresh air and air recirculation switch
• J353 – Rear fresh air/air recirculation flap relay, control
  number (94), in centre behind dash panel
• L91 – Rear fresh air blower switch illumination
• N45 – Rear fresh air/air recirculation air flap two-way
  valve
• N63 – Fresh and recirculation air flap two-way valve

Rear warm air blower

• E100 – Warm air blower switch, in dash panel
• J14 – Warm air blower relay, control number (53), in
  centre behind dash panel
• N72 – Series resistance for warm air blower
• S51 – Rear warm air blower fuse (20A)
• V47 – Rear warm air blower, rear on passenger
  compartment

Rear fresh air blower

• E179 – Rear fresh air blower switch
• J13 – Fresh air blower relay, control number (105)
• N10 – Series resistor for rear fresh air blower
• S97 – Fresh air blower fuse 1 (30A)
• V80 – Rear fresh air blower