Copper weight loss program
March 2010
Copper weight loss program
Separating TDI wiring from VW wiring

The whole VW wiring harness is a pretty complex piece of engineering. But when you break it down wire by wire it's not that bad. I wanted to keep everything needed to run the TDI plus retain things for A/C and fan control. I'm not sure if I'm going to keep the A/C, or which fan controller I'm going to use, but I wanted to keep my options open. I can always cut off more later.

I started the thinning by following every wire from the ECU to its end. When I got to the end I would determine what it was for using the Bentley manual and the termination type. Once it was labelled I could keep the plug if it was for a device I was going to use, or cut it off if it was going to to be spliced in to alternate vehicle system.

Below is a list of all the ECU wires and what their colours and function are. I'm not an expert on VW cars so I still have questions about what certain wires do. If you have any insight into these please speak up.

1GroundBrown408Chassie gound near ECU
2RPM OutBk/Gn408Dashboard in car
4Quantity AdjusterBr/Ye411Injection pump on motor
5Quantity AdjusterBr/Ye411Injection pump on motor
6Coolant Heater Relay LowBk/Bl410Coolant heater glow plug relay (VW) engine compartment
7Mod Piston Displacement SensorGr/Gn409Injection pump on motor
8RPM InputWhite408Engine speed sensor on motor
11Needle Lift sensorBlue409Lift sensor 3rd injector
12Needle Lift sensorGray409Lift sensor 3rd injector
13MAFBr/Rd408MAF sensor in intake
14Engine Temp.Bl/Br409Engine temp sensor on motor
15TPSWh/Bl410TPS in car
17Clutch Vac. Vent Valve SwitchWh/Rd409Clutch switch? In car
19MAFRd/Gr408MAF sensor in intake
20Brake SwitchWh/Ye409Brake pedel in car
2312V From Power Supply Relay (3)Bk/Ye410Power supply relay (3) (VW) engine compartment
24GroundBrown408Chassie gound near ECU
26Coolant Heater Relay HighBk/Br410Coolant heater glow plug relay (VW) engine compartment
28Relay position 1 Relay 85Br/Gr408??
30Glow Plug Relay 180 postion 16Gr/Wh411Glow plug relay (VW) engine compartment
33Ground, SensorBr/Bl409Sensors: brake, clutch, IAT, MAF, RPM, Fuel Temp, TPS, Engine temp
34Cruise Control switchBl/Gr409Cruise control switch. Converter box?
37A/C On Input? (high idle?)Gn/Gr410 
38Ignition Input?Black409 
42Power Supply Relay (3)Bk/Vi410 
43Speed SensorBl/Wh410 
44Brake Input?Bk/Rd408 
4512V From Power Supply Relay (3)Bk/Ye410 
47Wastegate Bypass Valve Solenoid (N75?)Rd/Bl411 
48Glow Plug Indicator LightBl/Gn411 
49Quantity AdjusterBr/Ye411 
50Glow Plug Relay #16Ye/Bl411 
51Cold Start InjectorBr/Bk411 
52Mod Piston Displacement SensorWh/Gr409 
53Fuel Cut OffWh/Bk411 
60Malfunction Indicator LightYe/Wh409 
61OBD-II Data LineGr/Wh408 
63Fuel Temp SensorYe/Wh409 
64Intake Air Temp. (IAT)Bl/Ye409 
66Cruise Control switchBk/Wh409 
6812V From Power Supply Relay (3)Bk/Ye410