80 Series rear Demister

[Gary Stockton]

I searched and found zilch, so quick q for the brains trust...

On the 80 series rear tailgate window are 2 electrical connectors on the demister. Question : are those both positive feeds or is one positive and one negative? If the latter, which is which?? I have no demister function so suspect a fault on the loom somewhere rather than on the window strips...
So before stripping out the upper tailgate (weather here is horrific - only 2 degrees outside ) I thought I'd check

Thanks guys

 

[Towpack]

One is + and one is - (earth). I changed my screen last year as most of the elements were blown but I can't remember which is which. You should get 12v with a meter across the terminals or across one of them and the body/chassis. If not then there's either a wiring or relay fault. Switch everything off and look for a short to earth from either of the terminals, this will be the neg wire, unless of course it's the neg feed thats broken!
If it stops snowing I'll go out and check!

 

[Gary Stockton]

Thanks - I'll go get into my survival suit and have a look .... glad you have snow, just high wind, cold rain in Edinburgh

 

[Gary Stockton]

Think there are poor connections .... voltage is there but not great

One for a warmer day!

 

[Jon Wildsmith]

Don't think I ever used it Gary, sorry.

 

[Gary Stockton]

That's what you get for not living in the Frozen North

Unfortunately with two large dogs in the back after 2 hours in the hills it doesn't take long to mist up so I'll need to get it sorted. No problems just a bit of fiddle I hope

 

[stumog]

I would claim warranty on that Gary.

 

[StarCruiser]

See if you can test the current drawn. You could rig up a temporary connecting wire from the Earth side to a chassis or body bolt somewhere. Also a temporary wire from battery + to the window + side and see if it improves. I suspect it could be a broken wire in the tailgate connections. This would show it up. You could also test withba multimeter set to volts across from demister earth connection to body which I suspect may be the fault. Most multimeters have a 10A current setting. You could insert this in a break in the wire (in series) to test the current drawn. Any wires need to be at least as thick as the oem wires.