Reverse light always on

[kes205 0]

Hi all

 

I have just noticed that my reverse light in lower valence didnt work. I took it a part and noticed there was no bulb in it. This gave me a sinking feeling as only bought the car a little while ago. Now on replacing the bulb the reverse light is always on no matter whether it's in reverse or not. Not sure how that passed the mot but anyway.  The car has a 3l v6 out of a 406 and gearbox just to make it a bit more complicated. Any ideas. ? 

 

[jackherer 543]

10 minutes ago, kes205 said:

Not sure how that passed the mot but anyway.

Reversing lights are not part of the test. The only way it could fail for reversing lights is if they are stuck on so that explains it.

 

Check the switch on the gearbox, either the switch is broken (stuck on) or the wiring is pinched somewhere.

[kes205 0]

Well changed switch and  lamp is still on. Disconnecting the reverse switch has no effect either the lamp is still on. Any ideas 

[jackherer 543]

The wires are either shorted together somewhere or shorted to ground then.

 

Look inside the reverse switch plug first, sometimes the pins on those type of plug can come unclipped and short together inside the housing.

[kes205 0]

Well doesnt look like they are touching. I used a meter to check if continuity between the wires of reverse switch plug and there wasnt. So maybe not the plug. 

[kes205 0]

Does anyone know if the reverse switch is breaking the live or ground of the circuit?

[jackherer 543]

I'd never given it any thought but it looks like it breaks the live side in the Haynes wiring diagram.

 

 

The switch is 83 and the tail lights are 69 and 70.

[Tom Fenton 1,524]

I’d say someone has got the wiring wrong during the V6 swap, couldn’t work out why, so have removed the reverse bulb.

[jackherer 543]

Ah yeah I forgot about the V6 swap.

 

Now I think about it some more it's possible the plug that was on the reverse light switch is NOT the reverse light plug, the actual reverse light plug could have been connected to something else by mistake.

[welshpug 1,621]

the ac compressor has a 2 pin white plug just like the reverse lamp though they are not very near each other.

 

as with any engine conversion the wiring goes through the 2 brown plugs so I'd start there and work forwards.

[kes205 0]

Well I checked the plug connecting to the reverse switch and either wires are not recieving any voltage with the ignition on or or off.  Think it must be some wiring errors in the conversion. Just trying to work out the engine bay wiring now. Found the brown multiplug the v6 loom seems to be spliced into. Just need to work out each wire.

[welshpug 1,621]

that looks rather shonky    the brown plugs i mentioned are under the dash near the steering column by the side of the heater box.

[kes205 0]

Yeah dont think it's the best to be honest. Will need to look at sorting it all or getting someone to create new loom etc 

[kes205 0]

Well finally sorted the reverse light in the end. The reverse light wiring from the 205 loom was cut and just happened the two reverse wires were touching. Hence the light always on. The 406 reverse switch  wires were cut and not connected to anything hence the no power to the reverse switch. Took ages to find after undoing  alot of insulation tape. Rewired correctly and the reverse light works as it should. 

 

The only thing is I have found a blue wire in the engine bay coming from the 205 loom which I havent a clue what its for.  No number on the wire and not part of sensor loom.  Juat additional wire. 

Edited June 19, 2020 by kes205

[karabas 21]

if its connected on the 7 pin brown plug, probably #46C for starter solenoid. if there is a direct cable from the ignition switch to the starter thats why its empty. If its not on the brown plug then #46 for SAD.