TheSamba.com :: View topic - Automatic backup light / safety switch

Sun Dec 23, 2012 7:15 pm

Oh no. I wiped off all the dielectric grease and used lithium instead. So what is wrong with lithium here?

Sat May 11, 2013 3:44 pm

BTW - if you look on the LH side of the shifter, you will see the detents and can figure out which position the lever is in (w/o having the console to ID them attached).

This procedure ought to be in the Bentley but I dunno where...

I would not use lithium grease on elec. contacts.

Sat Nov 09, 2013 8:59 pm

Can anyone please post pics of their connected wiring to the white part that the safety switch brushes against? Apparently the previous owner of our '90 Carat found that the neutral safety switch was broken, so took out the white plastic part, cut the thick red wires short and connected them to each other and I also seem to be missing a ground. I've compared to our non-running '89 Wolfsburg and there are different wires coming out of floor than on '90(which is why I think I'm missing wires on the '90). I will post pics tomorrow of both, but hope someone can help- I'm very frustrated with this mess. My mechanic added a toggle switch for reverse lights to get it through state inspection, which I've since learned is illegal. So I'm hoping to fix this right and correct the PO and mechanics hack-jobs. Thanks

Sat Jul 12, 2014 3:47 pm

blaze80 wrote: Can anyone please post pics of their connected wiring to the white part that the safety switch brushes against? Apparently the previous owner of our '90 Carat found that the neutral safety switch was broken, so took out the white plastic part, cut the thick red wires short and connected them to each other and I also seem to be missing a ground. I've compared to our non-running '89 Wolfsburg and there are different wires coming out of floor than on '90(which is why I think I'm missing wires on the '90). I will post pics tomorrow of both, but hope someone can help- I'm very frustrated with this mess. My mechanic added a toggle switch for reverse lights to get it through state inspection, which I've since learned is illegal. So I'm hoping to fix this right and correct the PO and mechanics hack-jobs. Thanks

I am in the same boat.
Are there anymore photos out there?

Sat Jul 12, 2014 4:08 pm

This is what I am looking at. I think the thick red ones are the neutral safety and must go top and bottom in front.

Not sure which one goes on top.

Anyone been down this road?

Sat Jul 12, 2014 4:36 pm

I didn't take a close-up of mine when I replaced the switch, but:

The big, fat red/black wires go on the front, order doesn't matter; but for the shape of your wires the one without the plastic insulator goes on top, the other on bottom.

For the back wires, IIRC, the black/blue wire goes on top, black/white goes on bottom. The Bentley manual diagrams show which wire color goes to which pin (pins on the switch are labeled). Then, there is a set of wires (blue power and brown ground in my '90) that go the shifter light bulb(s).

The ground wire on the "hump" goes up into the dash somewhere... in my '90 anyway.

When I put it all back together and verified everything worked, I got my label maker out and labeled the wires for potential future endeavors.

Sat Jul 12, 2014 5:49 pm

Thanks Kamz. You gave me just enough info to work it out. You come through an awful lot lateley.

Here is a pic for the next person.

Fri Aug 01, 2014 5:56 pm

blaze80 wrote: Can anyone please post pics of their connected wiring to the white part that the safety switch brushes against? Apparently the previous owner of our '90 Carat found that the neutral safety switch was broken, so took out the white plastic part, cut the thick red wires short and connected them to each other and I also seem to be missing a ground. I've compared to our non-running '89 Wolfsburg and there are different wires coming out of floor than on '90(which is why I think I'm missing wires on the '90). I will post pics tomorrow of both, but hope someone can help- I'm very frustrated with this mess. My mechanic added a toggle switch for reverse lights to get it through state inspection, which I've since learned is illegal. So I'm hoping to fix this right and correct the PO and mechanics hack-jobs. Thanks

My dude, on Sat Nov 09, 2013 you said you'd post pics tomorrow of your wiring situation but it's Friday Aug 01, 2014 and there ain't no pics. You have any? Because I'm in a wiring jam too!!

Wed Jan 04, 2017 1:48 pm

Bumping this excellent thread. I went to install an AUX reverse light today and discovered my reverse lights don't work anymore.

After basic troubleshooting, I went to the neutral safety switch. I cleaned the contacts and made sure it was adjusted correctly, still wouldn't get anything.

How to Test Neutral Safety Switch for Reverse Light Function:

The two wires that connect on the back side of the switch are for the reverse lights. The one on top powers 12v to the switch, test this with the ignition on with a check light/meter. If power doesn't show up, make sure your fuse is good. If it is, good luck tracing that wire into the dash!

If power does show, you can jump the switch by placing a length of wire/paper clip between the two wires. The bottom wire with the plastic connector goes to your reverse lights. If your reverse lights work with these wires connected, your switch is bad. This was my case, even though the contact points looked good.

Vanagon: +$50
Me: -$50 :roll:

Here is also a great video showing a new way (to me) to access these components, and refurbing your current pieces if purchasing new replacement are not within your budget. https://www.youtube.com/watch?v=3j5BZItWxTQ

Fri Jan 06, 2017 7:18 am

The new switch block + rubbing pad bind awfully when shifted back from drive to R,N,P.

I'm afraid I'll bend the delicate brass pad while forcing it back onto the block!

Anyone else have this problem?

Do you think tinning the surface with leaded solder would make it more slippery?

Dielectric grease alone isn't up to the job.

EDIT: after futzing about with it I could determine the fault was with the NEW switch block neutral contacts, which had a rather unfinished and abrupt edge rising far above the radiused edge of the block.

This causes (for me, at least) binding of the rubbing block when shifting up from drive into neutral.

My quick and dirty fix is to replace the NEW switch block with the OLD one, which is "nicely" worn. The original problem I had was the OLD rubbing block was worn completely through and had messy ragged edges at the contact areas.

The new one should be fine once I sand/radius/burnish the trailing edges to match the plastic of the block itself.