G/box: 5 speed M47: Reverse switch question

[Juular]

Just a quick question. I'm checking all aspects of wiring in my 240 before I put the interior back in and noticed that the reverse lights do not work.

I pulled the 2 pin plug at the gearstick and tested for continuity with the gearbox in and out of reverse but I get nothing.

Before I go ahead and lower the gearbox to change the switch, it was mentioned to me that the engine needs to be running.for this switch to work properly.

I just want to confirm whether this is or isn't the case - in other words should the reversing lights work with the engine off, key in position 2 and gearstick in reverse?

[Bob Meadows]

Not necessarily running but ignition has to be on:~
Access to the switch is fraught with difficulties with the engine in- switch isn't accessible as it is in the top of the box- it can be lowered from the rear but this again gives very limited access to the cable connections.

From memory the cables have push in connections above the box and this is a likely point that brakes the circuit if disturbed. It is important to make sure the the cables are held in place by the cable holder and routed properly around the gear lineage.

I would look at the connections first and then move on if required?
switches are usually good.

Blue air- bruised hands-kids asking Mum what are words that Dad is saying day!
Good Luck
Bob.

[Juular]

Thanks Bob.

I'm fairly certain it's either the switch of the wiring on the switch as I've been round the car and checked everything else. I may as well deal with this while the car is up on stands and the gearbox mount is off. It looks like fun!

[Clifford Pope]

You haven't actually said you have checked the fuse. Or is that a silly question?

[Juular]

Yes, fuse, bulbs, wiring all the way back is fine. The lack of continuity through the 2 pin plug at the gearstick is pointing me towards the switch or wiring near it.

[Bugjam1999]

On the subject of the reverse lights switch and for the benefit of anyone who has to replace this part of the wiring in the future, volvo used bullet style connectors within grey plastic outer boxes in various places on the 240, the indicators, the bulkhead engine loom connector, a connector near the coil etc. That are a perfect fit for the reverse light switch.

Simply unclip the grey plastic surround to release the individual bullet connectors within.

Photo of an indicator with the grey connector circled below.

Cheers

[Juular]

To bring this to a conclusion, and hopefully to help others, here is what I did.

I already had the gearbox mount off so I just dropped the box until the engine was resting against the bulkhead. As you can see, this still doesn't give you a lot of room and I could barely get my fingers near the switch.



The trick I used was to get a scissor jack, wedge it in between the tunnel and gearbox, and slowly open it up.



Once it goes as far as it can, access is much better and I could not only get crocodile clips on the switch pins, I could potentially get a socket in there to remove the switch.

Tested the switch by sticking the car in reverse and checking for continuity at the pins. All good in this case.

The wiring however was a different story, badly corroded and the end sockets had become very worn and loose.

Next, I bridged the pins on the wiring connector and checked to see if the reverse lights came on - they did.

To fix this I made up a little bit of extra wiring with blue crimp-on female bullet connectors.



With a bit of persuasion these fit snugly on the pins on the switch.

The trick to realigning the gearbox mount when you come to replace it, is to loosely attach one side. On the other side, shove a screwdriver through one of the bolt holes and use some force to lever / line it up with the holes on the chassis. Then put a bolt in the adjacent hole to pin it in place.

All sorted now! Hope this helps someone.