Z3 Heated Rear Window Does Not Work - Update

[MikeP]

Hi All,
I purchased a 2000 Z3 last autumn.
It came with a factory supplied hardtop and I have been using this all through the winter / spring but have finally removed it and am really enjoying the roof down .
The hardtop was great during the poor weather but I could not get the heated rear window to work.
Now that the roof is off I have checked the two contacts in the connector in the car and I am getting 12V when the heated rear window switch is on and I have checked the two contacts on the roof locating pin and I have a circuit so it looks like the element and roof internal wiring are OK.
This suggests the problem is in the way the two halves of the connector line up when the roof is fitted
Has anyone had this issue and found a way to solve it?

 

[Pond]

Now that the roof is off I have checked the two contacts in the connector in the car and I am getting 24V when the heated rear window switch is on

I really hope you are not getting 24v. If you are you may have a lorry battery fitted.

 

[MikeP]

Sorry - obvious typo, should indeed read 12V - have corrected original posting

 

[MikeP]

Hi All,
Winter is fast approaching and before too long it will be time to re-fit my hardtop so I am re-visiting this thread in the hope of solving this problem before the inclement weather sets in.

I have been searching posts here and on Bimmerforums and a number of people have mentioned about needing a relay in the main fusebox.

I have checked and, as far as I can, see there is no relay fitted in my car however I do get power to the terminals in the hardtop mounting bracket when I turn the switch on which I would not expect if the power was coming via a relay?

The roof was fitted by a BMW dealer so I wouldn't have thought they would miss something as fundamental as that and the owner at the time would surely have gone back to the dealer if the heated rear window was not working.

 

[Duncodin]

You said you have power at the terminals so not a missing relay.

You need to check the power at the element. I can't remember if there's accessible terminals where the wires connect to the element but that's where you need to test if you can