Reverse switch.

[Bodzer]

One last topic for today. I have installed a new reverse switch into the side of the 336 gearbox I have. No matter what depth the switch is, it’s always on. Any ideas on what I’m doing wrong? It is in the hole where the previous switch was.

Thanks.

[BDA]

I assume the previous one worked at least for a time. Is the new one longer?

[Bodzer]

Hi BDA,

The contacts had broken off. The car was a non-runner when I got it. I’ll have a root around the garage but I think it was binned (cardinal sin during a restoration I know). I sourced the new one from Banks.

Cheers.

[BDA]

I would not be surprised to find that all Renault transaxle use the same switch. With the possibility that I am wrong, I would not expect Richard to send you the wrong one. 

I am further assuming that you have been able to select other gears. I was going to say there should be a washer to effect a seal, which is normal for straight thread joints, but there is not one on my NG3's reverse switch.

If there is no other resolution, you could use a copper or aluminum washer, but you should eliminate all other possibilities first and that implies that you are reasonably certain that the gearbox is in reasonable, useful condition.

[Bodzer]

All gears engage and turn. There is an aluminum washer too. Thanks for the help.

[Grumblebuns]

Are the contacts OPEN or CLOSE with the switch removed from the gearbox?

I believe the reverse switch is a normally OPEN when not in reverse and the switch ball actuated. When reverse is selected, the ball switch is released and contacts closed. My pictures may make my explanation more clear. The switch on the 336 did not have any washers.

I would try to exercise the ball switch several times to clean up/free up the internal contacts.

[jbcollier]

Remove the switch, hook up the wires and make sure the rev lights go off when the ball is depressed.  If not, duff switch.  Next, compare the lengths of the threaded shaft of the new and old switches.  New one too short?  There's your answer.  Everything checks out?  Removes the alloy sealing washer and try it again.

[Bodzer]

Thanks Joji and JB. A picture tells a thousand words. The switch is on when the ball is out and off when the ball is depressed so it does work correctly. I shall remove the washer and try again.

[Bodzer]

JB called it. It was the washer. The difference of a millimeter made all the difference. Thanks for the help.