XSeries-forum

Long story short

I've broken the rear glass twice now......once when someone bricked it and the 2nd when I left the tailgate up at the tip
Anyway, that's the background that may not be related

Not long before the 2nd breakage I suspected the rear wasn't working but being warm it wasn't perhaps obvious. Now it's cold (post 2nd replacement) I definitely know its not working as the air inside is what eventually clears it

Things tried

Engine running button pressed lights up
Thought it might be the 30 amp fuse in the rear side compartment (near fuel filler) but a test has proven there is 12v either side
Swapped the relay nearby and that appears to be working to

Removed the trim inside near the top of the window and I could see the two wires with a plug from the glass going into what I think is called the diversity unit on the drivers side. One the passenger side is another plug which I think is the power to the diversity unit/glass. Testing the passenger (in) side I could see 12v but prodding the wires on the glass (out) side got no voltage at all

The radio reception is fine so maybe the aerial is working
The remote which I think uses the diversity works fine too

Tinterweb suggests that simply swapping the diversity with a 2nd hand unit MAY temporarily un pair my key in some way which is a high price to find out and be knackered

What have I missed or not tested to figure out the fault?

Check voltages going directly to the element.
Also check the element for continuity/resistance value.
Some modules will not provide power if there is no circuit sensed for it to feed.
It protects against shorts, over heating etc..  sometimes too clever for its own good!!

I thought the aerial was in the side glass??

Re-pairing keys is not an onerous task.
Search on here will provide you the procedure to do so.

[quote="Steamyrotter"]
Check voltages going directly to the element.
Also check the element for continuity/resistance value.
Some modules will not provide power if there is no circuit sensed for it to feed.
It protects against shorts, over heating etc..  sometimes too clever for its own good!!

I thought the aerial was in the side glass??

Re-pairing keys is not an onerous task.
Search on here will provide you the procedure to do so.
[/quote]

Check voltages going directly to the element.
I think I did that by using a multi-meter on glass side of the diversity unit...there are two wires and grounding either showed ZERO voltage

Also check the element for continuity/resistance value.
Didn't try that....to do that it will be panel off to expose the only known connections to the glass grid (any others folks?) plugging into div unit. I'll pull the plug and check that way

I thought the aerial was in the side glass??
Possibly is but the div unit has going into on the nit is what looks like a slim aerial lead as well as the perceived power plug (3 wire plug I think). This plug DID have power which seemed but half a hand away from where power could go to heating grid

Here's an example image of where I've been looking for power....which on reflection might mean I'm looking in the wrong place and this is just the aerial :'(

Not my images though

https://www.bmwgm5.com/Images/FZV/FZV_X5_Location.jpg

https://www.bmwgm5.com/Images/FZV/FZV_X5_Module.jpg

Well I've still not got it working but i'm nearer to knowing what's the problem

All fuse checked and ok.

Power at the relay at two pins, one the main and the other having pressed the button. This was confirmed against the wife's X5 as how it behaves.

The relay is working as with the engine running and the switch for rear heat on I pushed the relay in and hard it click

One the wife's I can detect 12v on the grid when measure to an earth....on mine...nowt

I did a continuity between what I think is the relay contact to the grid...nowt

Conclusion....the power switched from the relay is not making it to the glass

The answer then if anyone can help is where does the heated power supply connect to the glass?

I don't think it where the diversity unit is near the LED brake light but somewhere else. The cables must surely go through the tubing between the body and the tailgate but its well hidden. If I could find the connector I could better establish how to fix it


anybody?