When it's extremely cold outside something goes wrong in my 340.
Doesn't work:
- Low beam
- Window wipers
- Window sprayers
- Interior fan (does heat up, but doesn't blow air)
- High beam won't stay on

Does work:
- Everything else, so parkinglight, brake lights, signalling with the highbeam, turning indicators, etc.

What do al these not working components have in common?
I've had this a couple of times now, but everytime it turned back on after a couple of minutes of running the engine. Untill this morning when I had to drive to work without the low beam. Luckily the parkinglights are quite bright, but it was freggin' freezing in the car..

It's strange that it affects al these different components. I checked the fuses, they're all good and aren't on the same loop.. Do I need to look at relais? Do all of these share the same? Or perhaps a shared mass connection somewhere in the dash?

Its possible the low temp is chilimg the old wire so much its reducing current flow. its not common but does happen. a more likely option would be stiff relays. But i can't say for positive these ideas are your issue. try things like flashing your lights rapidly see if it makes anything work faster or put your car up to 3k rpm a few times things like that. or try a bigger battery.

Logan360 wrote:Its possible the low temp is chilimg the old wire so much its reducing current flow. its not common but does happen. a more likely option would be stiff relays. But i can't say for positive these ideas are your issue. try things like flashing your lights rapidly see if it makes anything work faster or put your car up to 3k rpm a few times things like that. or try a bigger battery.

Lol, it's a 20 minute drive to work, I tried EVERYTHING i could think of on that trip.. From hitting the dash to flashing the highbeam, switching stuf on and off, what strikes me as odd is that all the other things work like they should. Even the dash lighting and stuff.. Is there an electrical schematic that shows all the components in one scheme? Instead of those drawn by a 12 year old and devided into sections in the manual?
What I will do is measure the battery current on my next break. Though I wouldn't think everything else would work properly if that was the cause..

Check all the earth points, mine went a bit crazy when I forgot to tighten the body bolt by the battery on the earth strap. Checking my stripped down car I can only find another common earth on the other side of the battery tray.

Ride_on wrote:Check all the earth points, mine went a bit crazy when I forgot to tighten the body bolt by the battery on the earth strap.

Yes, I can confirm that too! Warm weather no problem, the moment the temperatures went down the car wouldn't even start (even though the clock worked, interior light went on etc.)

Cheers

Tom

There is a little bimetallic cutout-device within a coil resistor box inside the black heater box. If the bimetallic cutout is frozen, corroded or broken, the heater fan will not work, full stop. The rest sounds like the under-dash relays. There are three connector blocks to the fuse box each side of the bulkhead - if you get really desperate they are worth a check, too.

Common thing for all of that is so called X relay, which supply switched 12V (electrical contact nr 15 in schematic).
It is situated under the dash, somewhere in the middle, left of key- for LHD model.
It is metal square with 4 wires on.

Never saw RHD model so maybe is different location.

On schematic you can find it as electrical contact nr 75.

It could be also key switch.

It should click and you feel under fingers when turn key in drive position.