Plugs with nothing attached - what do they connect to?

[Jonas_R]

So I found these two plugs while installing my Zeitronix.

1st one is left hand side of the car under the steering wheel. A little red one.


2nd one is right hand side of the car at the vacuum sensor.


Any suggestions what the plugs could be for?

[S2central.net]

The 6-pin black one looks like the infamous 'coding plug' (aka T6d on the schematics) - the only official/documented use that I can recall is on the RS2 when factory fitted with towbar option - some pins in that loom are used to tell the ECU to reduce boost when the tower is hooked up... Apparently doing 4-wheel drifts at high boost while towing a caravan is a bad idea. The coding plug could have other uses such as invoking the speed limiter when fitted with winter tyres. Someone like prj and his intimate knowledge of the Motronic code could likely find or create other uses for it.

The little red one with the brown/white wire would take more finding on the wiring sheets, but that colour convention tells me its a switched earth of some sort - probably for an option that your car wasn't built with.

[S2central.net]

PS - coding plug is great place to find 5V reference coming from the ECU !

[mike74]

Isn't the red one for the airbag?

[RichLV]

Isn't the red one for the airbag?

If I recall correctly, airbag has a 2-pin red connector.

[S2central.net]

Yeah its definitely not airbag related.
I am doubting the wire colour that I stated as brown/white on that red plug... Normally the single red plug would carry red/blue wire for brake light signal - to a trailer loom or high brake light in some territories.

[Jonas_R]

Maybe I should check the vin and see if it came with some sort of towbar option.

[S2central.net]

See if you can trace where the wire in that 1-pin red plug goes to... please confirm the wire colour and what model year your car is - hopefully its hiding in a schematic somewhere !!!