disconnect battery neg lead before you mess with wires at the BCU... and concentrate to not mix plugs/wires there and dont use thinner wire than the original that's all... good luck
 
I unplugged the yellow plug from the BCU to test pin 8 with ignition on in reverse as it should be getting power right?

No voltage to that pin at all.
 
Aaaarghhh.... don't mess with the BCU with ignition on cos it's not healthy.... by unplugging that connector with ignition on you broke the data bus with the IDM that's why you dont get signal, if you connected it back, disconnect battery, do the bypass, reconnect battery, put ignition on II and let it so 5 minutes then try the reverse
 
ive gone back a step and checked the plug under the window switches and there is no power from there
 
plugged the yellow plug in and all seems good, by that i mean dash displays gears so back as was
 
you was lucky then..... if there's no power on the GN wire you should not get the R symbol on the dash.... stop a bit cos i have to check the diagrams again ... something is strange here
 
i'm on it... i dont have an auto myself to check on mine that's why is hard..... switch on the front wipers on intermittent mode and select reverse, do the rear wiper come on this way? ... if not it seems that the LCD is getting the signal from the X contact of the XYZ switch but that's against the diagram and description.... we'll figure it out no worries
 
When you say you checked under the window switches do you mean at C0681 on the GN wire? ... if yes you'll have yto make an ultimate test which is not easy to check for voltage with reverse selected under the car at C0675-1 XYZ switch's loom also GN wire, if no voltage it means the switch is the problem and i'm sorry you made thsese measurements but RAVE is wrong in the BCU's description at a point cos according to it the signal for the R symbol is the same with the one for reverse lights but it seems it's not
 
... just double check your multimeter on the battery to make sure it works on DC cos that's really strange that you dont have voltage to BCU
 
I've checked the meter all along, found which wires were live.

I will try to get to the plug under the car and I guess if no power then its new XYZ switch time?
 
Yes, if you get there to the switch's plug bridge pins 1 with 2 (GY) cos on 2 there must be the live from F25 which gets to pin 1 when reverse is selected and if you select reverse and no reverse lights but with those pins bridged you get reverse lights then it's 100% the switch... though i'll never understand why they messed up the R symbol so as it gets signal from somewhere else against all the descriptions
 
Well rolled under the car, saw the plug, even managed to touch it but without removing the exhaust I think that's as far as I can go.

I will resume the switch is faulty but as its causing no other issues I will live without reverse lights or parking sensors for now.

Thanks again for all your help. I have in fact learnt quite a bit about car electrics.
 
Sorry to hear that, that plug should be accessible without removing other things, i asked around about that oddity with the R symbol ad the rest of reverse signal circuit but no answer so far .... at least you know what to check from now, i'll keep you informed if i find out something about this thing
 
This thing is a real challenge for me and i keep thinking about it...make only one simple test when you get to the car next time, remove F25 and see if you still get the R on the dash or not...that would clarify things a bit about that R symbol trigger
 
If it helps. I bought two cheap switches on Ebay and they both didn't work. I decided then to buy a genuine part and hey, it works.
 
The dillema remains untill now cos nobody seems to think that the R is triggered by other circuit so make that test with F25 removed and if the R still comes on i'll dig further
 
You must log in or register to reply here.

Similar threads

S
Reverse switch wiring
Replies
2
Views
555
Shore968
S
G
Reverse light
Replies
11
Views
753
TrevD
T
R
D2 2004 BULBS
Replies
6
Views
316
tilly2
T
D
Disco 2 Auto reverse lights
2
Replies
21
Views
2K
Davidmac
D
R
LED side lights not working
Replies
9
Views
750
RickyFreelander
R