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MG MGB Technical - Back up light switch

Bsck up lights quit working, discovered electrical conector had broken off (rusted) any idea on how to get the switch out, small tight spot, and looks like it takes a 1 1/8 inch wrench?
Kermit Witherbee

Lower the rear of the gearbox on a jack by removing the four cross-member to chassis rail bolts and that should give you enough room to get at the switch. Removing the arm-rest cubby (where fitted) and tunnel carpet will also reveal a removable panel, large on a 3-synch car which is a great help, but even the small panel on a 4-synch gives a bit more access from above. Channel grips will probably unscrew the switch. Watch out for any fibre spacer washers on the old switch and change them over, they are used for adjusting the switch position. Check functionality of the switch with battery and bulb not an ohmmeter before fitting to the gearbox, and check functionality again with the switch in the gearbox but before replacing everything else. Be aware that no-name switches may fail in a very short time, it's not uncommon these days to have to fit a relay to protect switches from the load of the lamps, and also a diode to protect the switch even from the relay!
Paul Hunt 2010

I was able to change mine with the car on ramps. It's a tight squeeze, and requires a bit of patience, and probably a few non-repeatable words, but I was able to remove the old switch and insert a new one.
Pat
'73BGT
Patrick Callan

I replaced mine last weekend (almost) without problem. I just put the car on axle stands and crawled underneath. I used a pair of plumbers pipe grips to remove the old switch and to tighten the new one. Make sure you replace the same washers as it came off with, I thought I'd get away with removing one of the two on mine - it worked when cold, but when the car got hot the reversing lights came on permanently as the switch made permanent contact with the heat expansion. As I was on a run, I had to unplug the reversing lamps to get the lights off.

I'll be crawling underneath again tomorrow to replace the second washer!
Mike

To ask another question, my backup lights would come on in 4th gear until I disconnected them. Do I need to add or subtract washers to adjust the switch?
Thanks, Mike
Mike Crowley

Mike - add.
Paul Hunt 2010

This thread was discussed between 25/06/2010 and 26/06/2010

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