UK 1994 1.6 Escort L bizarre electrical problem...

My Escort's just developed a strange fault where my rear windscreen wiper 'rarely' works, it can start working after a delay of anywhere between 30 seconds and 10 minutes, it then sometimes stops 'mid wipe'.
When I have my lights on, activating the rear windscreen switch also switches on my fog light and front windscreen heater.
Any ideas what this could be?
Thanks.
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BAD GROUNDS!! (earth connections for you brits)
Ted
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"Ted Mittelstaedt" wrote

Agreed. And for those who say "What? How would that cause this type of fault", the power tries to get to ground somehow, and if it can't get there through normal connections, it will travel backwards through whatever other "inactive" device is on the same circuit. That's why you occasionally see a car with one bright and one very dim headlight; the dim one's power goes through its own low-beam filament, then through its hi-beam filament (instead of to ground), then over to (and through) the other headlight's hi-beam filament, where it finally finds a ground. Too much resistance for full-current flow, so the "bad" side is just barely on.

You only need a small current (either direction) to switch on the control relays.
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