Odd heated rear window behaviour

[Grenouille 4 1 Cars]

Whilst rebuilding our 1991 1.6 GTI I've noticed some odd behaviour from the heated rear window switch and looking to see if anyone has seen it themselves.

 

When the ignition is on, but engine not running, if I switch on the heated rear window, then switch off, the fuel pump primes. I should say that the fuel pump primes when I turn the ignition on (as you would expect).

 

Has anyone seen this? I can't see why it should but it's hard to tell if this is a result of some odd electrical gremlins or some weird French electrical thing.

 

Thanks in advance all! Andy.

 

 

[PhilNW 66]

Is the heated rear window actually working?

 

When odd things like this happens , a dodgy earth is often a cause.

 

Wiring diagrams can be found here http://prepparts.free.fr/docs/doc2ter.html

 

Google translate is useful 

 

[Grenouille 4 1 Cars]

Hi, thanks for the reply. The heated rear window is working, or at least getting 12V.

 

Dodgy earth was the original thought but unable to find it if there!

 

Wondered if it had anything to do with the relay 6 board issue mentioned a few times within the forum.

[PhilNW 66]

Use a steaming kettle or carper steamer to confirm an actual working rear heater. Be carfeful!!

 

Try using a dedicated earthing wire from the heater to the battery to bypass any dodgy existing earths.