Vauxhall interior map lights

Any plain brown wire is an earth wire which is connected to the chassis of the vehicle. Positive feeds are red for permanent +12v (fused KL.30 on the inside of the fusebox lid), and black for +12v ignition feed (fused KL.15). You may have a grey wire at the lamp which is connected to the door switches.

As for the diagnostic plug, it is unlikely that the ECU is OBD2 compatible, as most Vauxhalls used a different diagnostic standard until about 2001/2 for petrol models and 2003 for diesels (this is also model dependant).

HTH

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