Bongo Fury

I have one of the above clocks fitted in my bongo. It was working Ok until a few weeks ago when it would not work. So I ordered another from E-Bay . I put the new one in and it still would not work. I say would not work , but it only works when the ingnition key is not inserted , as soon as it is the clock stops working. Anyone got any ideas as to why this is?

I'd initially suspect an earth problem.

If you have a multimeter you could do some checks at the clock terminals to confirm.
Alternatively try a temporary earth to the clock to prove/eliminate.

Thanks CMM303. I thought it might be an earth problem, but wanted to double check. I will try a multimeter on it . Thanks