The reversing light switch on my 123GT is not working. It is the switch with the aluminum cover which screws onto the back of the M41 gearbox just above the output shaft. It has 2 phillips screws.

Everything else works fine, if I ground the correct pin on the relay the lights come on.

I can see the switch if I remove the rubber bung from the transmission tunnel, also if I crawl under the car I can see it as well.

Looking at the GCP diagrams it appears that there is a contact in the side of the aluminium cover which hits one of the gearbox rods when in reverse. They are available and I ordered one.

It's a small rubber nubbin thing with a spade connector on one side and a bolt thread on the other.

My problem - is there a trick to replace this? Do I have to drop the transmission ? Is there a way to undo the 2 screws from the hole in the tunnel? Can I replace the nubbin only or do I have to get the whole switch out?

Thanks everyone!

Andrew