HELP heated mirrors not warming up

[Deaky]

Also check again with the rear screen demister on

 

[roooms]

Thanks Deaky but I don’t have a rear demister. I saw your comment on another thread and hoping that’s not possible in my case. Mine was a panel van and now has glass in the tailgate but no demister or wiper.

 

[roooms]

Ok, I spent some more time trying to troubleshoot this today and realised I just don't understand electrics, so hoping I can continue to get some help here...

I joined the forum membership (thought I'd already done that) so I could access the downloads section and spent some time reviewing the PDFs. I also used this page on fuses and relays to try and confirm everything.

Heated Windscreen
I left my heated windscreen on while I was trying to troubleshoot the mirrors and it is actually heating up! So that doesn't seem to be an issue unless some of the 30A fuses (8 and 26) in fuse box B near the battery were dislodged, but I tested them all and they seemed fine.



Heated Mirrors
I found that with both mirrors disconnected, I get ~7 volts across the white and brown wires. I don't get any voltage reading if one of the mirrors is connected. I re-checked SC17 and SC30 in fuse box C and they are both fine.



Leaving the mirrors on the heat setting on the mirror switch doesn't ever seem to make the mirrors warm like the windscreen and if they were working you'd actually be able to tell eventually by feeling some warmth. The voltage seems to be constant and isn't affected by the heated windscreen button or the position of the mirror adjuster switch (folded, left, right, heat), so I'm unsure what to make of that. Doing a continuity test, I get a tone when one mirror is connected and I am testing the terminals on the other mirror wires (mirror removed). This to me suggests a complete circuit is ok, but again, not sure how that helps if the mirrors still aren't heating up.

Any (more) help appreciated. Thanks!

 

[Loz]

What do you get between the white wire and the other probe on a chassis earth, this will check the negative(brown wire ) connection to the chassis

 

[Gazza1]

Did you ever get to the bottom of this problem. I've got similar issues, fuses fine, replaced glass both sides, no voltage at terminals. I've just ordered a new switch as the final stab at solving the issue.

 

[Deaky]

Did you ever get to the bottom of this problem. I've got similar issues, fuses fine, replaced glass both sides, no voltage at terminals. I've just ordered a new switch as the final stab at solving the issue.

Do you have a rear screen demister?

 

[Gazza1]

Do you have a rear screen demister?

No rear demister, I've read all the main posts so aware of the demister being the master when present

 

[roooms]

I haven’t solved it yet. Van was in the garage for some other work recently and they took a quick look at this issue but couldn’t find any obvious failure. They’ve suggested booking it back in for full diagnostics when I next have other work done (which will be end of February).

 

[Gazza1]

hi every one.

my heated mirrors on 2016 T6 are not heating up anymore. when i plug vcds in and test the output, they work fine.
its had a new switch fitted, im assuming the fuse and relay is good, but maybe a bad connection between the switch and the mirrors, its both mirrors that are not working.
any help or advice would be greatly appreciated. mileage 173500. mirrors are folding ones.

dave

Ok, so I've got a bit further with this issue and I'm now in exactly same position as opening post (above). I plugged in an OBD Eleven device and ran an output test on the heated mirrors, could hear the relay click and new mirrors warmed up immediately. I've replaced switch but still the mirrors don't heat up when in the heated position. Anyone have any ideas given the progress I've made.

 

[mmi]

Ok, so I've got a bit further with this issue and I'm now in exactly same position as opening post (above). I plugged in an OBD Eleven device and ran an output test on the heated mirrors, could hear the relay click and new mirrors warmed up immediately. I've replaced switch but still the mirrors don't heat up when in the heated position. Anyone have any ideas given the progress I've made.

Does the switch talk to you?
Please verify the switch at OBDeleven > Control units > 09-Central electrics > Live data > Channel 032 > Value 3
What's the value? Should changing between Off/ON when the switch is operated.

 

[Alster]

It’s no expert on this but could it be low battery voltage or a temperature sensor somewhere or possibly connected with the stop/start as when it cuts in certain electrical devices are switched off (heated seats for one)