[urq] Foglight relay is not switching if engine runs

Maurits Jonkergouw urq at moregraphics.nl
Sat Nov 29 12:13:34 EST 2003

Somehow the foglights never worked on my '85 CGT, and after investigation,
the foglight relay terminal 85 does receive 12V from the main light switch,
but fusebox terminal 10 (86 on the relay) is not connected to earth and
hence does not switch terminal 11and 13 via 30 and 87 in the relay to power
the bulbs.

A. There are two spare M5 earths points in the box. I jumped relay terminal
86 with the M5 closest to the front of the car and yes, the foglights work
when the engine is off, but strangely enough, when the engine is running,
they don't.

B. When I bypass the relay (J5) by jumping 11 and 13 on the fusebox with a
piece of wire, the foglights turn on again even when the engine is running.

My best guess would be that the relay 'looses' this earth on terminal 86
when the engine is running and opens the relay via 11/30 and 13/87 again,
turning the foglights off...

Any idea how to fix this or why this is happening?

Thanks a million (MOT in 2 days from now).


'86 quattro GV (WR)
'85 coupe KV
'82 coupe DD 

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