Vectra c 52 no reverse lights any help appreciated

[barks]

Hi all
ive just picked up a vectra c on 52 plate with a few probs cheep while I'm between jobs.
The first job is no reverse lights. So far....

bulbs ok. Bulb housing wiring and connectors ok to boot fuse box.
Reverse switch ok. I have 12v at the switch on white/black and when in reverse I get 12v out on the brown.

im assuming the brown continues through various connectors to the boot and plugs into the fuse box. I can only see one brown wire connected into the fuse box and it has no voltage so I'm guessing there is a break or bad connection somewhere.

Can anyone confirm which wire plugs into the fuse box from the reverse switch? And also the journey it takes and does it stay the same colour?

Many thanks
barks

[richy1974]

How do you know reverse switch is ok. I got a brand new one for a golf a few months back after checking various things found out the new switch was faulty

[barks]

How do you know reverse switch is ok. I got a brand new one for a golf a few months back after checking various things found out the new switch was faulty

hi.
I have done a continuity test on the switch and its fine. As stated giving me 12v on brown when in reverse.

Im going to have to unplug all multi plugs and trace it tomorrow.

[maud2450]

Haynes manual show white/black wire comes from engine bay control unit,giving you 12 volts on switch, and brown wire goes to chassis,so disconnect brown wire and continuity test to chassis.if okay then,you will need to check rear fuse box control unit,where again white and black should have 12 volts on it when in reverse.
You say you have 12 volts on brown how are you testing it and is it relative to chassis m8

[barks]

Haynes manual show white/black wire comes from engine bay control unit,giving you 12 volts on switch, and brown wire goes to chassis,so disconnect brown wire and continuity test to chassis.if okay then,you will need to check rear fuse box control unit,where again white and black should have 12 volts on it when in reverse.
You say you have 12 volts on brown how are you testing it and is it relative to chassis m8

Thanks maud
when in reverse I have 12v between chassis and brown wire at switch so from what you have stated there must be an earth fault on the brown. Ie it should be connected to chassis.
Am I right then in saying the engine control unit applies 12v to the switch and waits until the 12v is grounded then communicates with the rear boot fuse box to apply 12v to the reverse lights ?
cheers
barks

[Critch]

Sounds like open circuit on brown wire mate

[barks]

Sounds like open circuit on brown wire mate

Yes mate.
I would never of expected a 52 plate vectra to have a data communication between front and back. Makes sense less cables ect but on a 52 plate I'm amazed. I also learned today that the rain sensors close the windows if it starts raining. Lol
to test if I short the white/black to ground at switch the reverse lights should come on. The switch dosent have diode or resistance so 12v must be transistorised. .

cheers
barks

[Critch]

The ecu will put 12v and watch on line waiting for it too be pulled to ground.

use a test light on white wire and see.

test light is slightly safer than just using a jumper wire.

[Critch]

Should have also said that it will either power or ground the cicircuit if its ecu controlled

from here I can't say what it is as I don't have diagram in front of me.

[barks]

Should have also said that it will either power or ground the cicircuit if its ecu controlled

from here I can't say what it is as I don't have diagram in front of me.

Thanks critch
i tried to find a wiring diagram but no joy.
Cheers again