Nissan: Electrical Problem - 1996 Primera

Hi

I was hoping someone here could give me some advise on how to track
down this problem.

When it rains, my stereo develops an intermittent problem. The radio
works fine , but when i use the tape or cd all it does is constantly
switch on and off.

I know the cd/tape uses more power - so it's some sort of voltage ,
earth problem. But the fact it only happens when it rains - i'm not
to sure where to start.

Fuse box and connections look ok. I know it's not the unit itself as
it works ok when driven by a power source. So therefore some sort of
wiring problem. This also happen last year with a different unit.

Any insight would help

Cheers

John Jenkins