1990 RRC: Heated rear window affecting door mirror operation

It sounds like there's a faulty earth connection somewhere.

Dry it out, then go looking for Lucas Prince of Darkness problems. Dodgey connectors, corroded and or leaky.

In particular, check and re-check all the earth (to body) ground connections. Many "odd" automotive electrical woes are often down to a ground, that isn't as "groundy" as it used to be.

Idealy, you need a 4 terminal ohmeter, but removing, cleaning and re- assembling them is a good move. Any bad ones, & you'll find them that (if tedious) way.

If you have a manual with a full schematic. Try to identify any "common" grounds that serve all the seemingly affected (and eroniously interoperating) systems, and start by looking at them.

Have Fun! ;-)

Dave B.

"Richard Savage" wrote

Could possible be the old "earthing " problems, a lot of us chaps with old Landies have put in extra wires connecting the main earths together and back to the battery so not relying on earthing through the engine/vehicle. Made a difference to my vehicle.

I had a Granada Scorpio ('93) that got a flooded Fuse and Relay box, the result was equally spectacular , I had a very Random Disco, Random Sun roof, Locks , Lights and windows. Oh what fun!

Whilst Earths may be the root... I'd be looking at the next common link between all the devices you are having fun with. Fuse / Relay boxes.

Lee

Thanks to all.

I really hoped someone would say something like: 'ha ha that'll be a faulty wotsit made of unobtanium' so that I could happily ignore the problem. I really don't fancy chasing earth faults - which is what I expected you to point to. I do have the wiring diagram as bedtime reading.

I suppose it's as good a way as any to spend Christmas day

Alternatively I could try to create a CAD version of the wiring diagram to make it just a little easier to read.

Richard ;-)

Well I suppose it's always best to try the most difficult and time consuming checks before starting with the b********ing obvious ;-) Grovelled around trying to trace Earths etc then got bored and looked at the HRW connection with a meter. The lead which connects power to the screen had fractured in the wretched tube-thing at the top of the rear window. 20 mins careful work with a soldering iron and heat shrink sleaving plus a little work with cutters to remove the cables to the non-functioning tailgate lock and discarding the tube thing and Bingo: nothing.

Arse! I then replaced the blown fuse in the dash ;-(

Mirror operation still entertaining but at least the Chinese laundry effect at the back is controllable. Next task is repairing a break in one of the HRW tracks.

Happy New Year to all

Richard