View original topic: Automatic backup light / safety switch - a tutorial w/pics!! Page: 1, 2  Next
deprivation Fri Apr 16, 2010 12:21 pm

When I first adjusted my automatic back-up light /neutral safety switch a year ago, I couldn't find a picture of the area anywhere - even the Bentley. It sure would have helped to have some kind of guide.

I'm in the middle of some soundproofing so I decided it was time to replace the switch and take a few pictures for future Sambanistas. I've gotten some amazing help here lately and I would like to add as much back as I can.

This is where the switch is located. You'll have to remove the 4 screws that hold the automatic shift housing. The carpet can be stubborn. You'll have to be mindful of the little lightbulbs that are inside the housing. You can do this without taking the shift housing entirely off but if you do want to take the housing off, you will also have to remove the shift knob. It is held on by a small allen-bolt inside on the right side of the knob.

Make sure you disconnect the battery before you do any electrical work.

The switch is held in by two screws. The switch has slotted mounts so that it can be adjusted to make a good connection to the contact surface which is attached to the shifter.

I used a VOM to check my switch adjustment. You'll need to check the leads closest to the firewall for "PARK" and "NEUTRAL". The leads with the small wires you will check in "REVERSE" only. By the way, I didn't zero out my meter, which is why it shows some resistance.

Also, it wouldn't hurt to get some super-fine 800 or 1000 grit sandpaper and clean the contact point. If it is really worn you will have to replace that as well. While you're in there, take this time to clean up the linkages to your shifter and put a little grease back on. I have some lithium grease that seems to work well on surfaces like this.

randywebb Fri Apr 16, 2010 1:09 pm

thx much - I am saving that

powderedwaters Fri Apr 16, 2010 1:17 pm

=D> Nice one!

madspaniard Fri Apr 16, 2010 1:24 pm

great job! bookmarked for my next project

deprivation Fri Apr 16, 2010 3:59 pm

Someone just PM'd me that this switch is really the neutral safety switch, which is actually a more accurate description of the switch. Though it does control the backup lights, it's main job is to prevent you from engaging the starter when it is in gear.

syncrodoka Fri Apr 16, 2010 4:14 pm

Quote: neutral safety switch

PDXWesty Fri Apr 16, 2010 4:17 pm

You can actually buy each part seperately too if you wanted.

tclark Fri Apr 16, 2010 7:41 pm

more sources for neutral safety switch components

mordeaux Fri Apr 16, 2010 8:34 pm

Related query: is there any adjustment of the detent for the automatic lever?

There is enough free play in mine that sometimes when bumping over, uh, bumps, I hear a relay clicking on and off. I also have a kooky scenario wherein when I put the trans in reverse, the pax side turn signal light comes on steady and when I put the right turn signal on, the reverse lights flash. Ha ha! Wacky...

johnnyfive82 Wed Jun 02, 2010 11:15 pm

how do you take off the contact point.

r.e.wing_fc3s Thu Jun 03, 2010 8:40 am

ive read this switch also effects the idle valve. anyone know what it does and why?

randr Sun Dec 19, 2010 6:41 pm


66 dormi Sun Dec 19, 2010 10:37 pm

Thank you! an other thing that just broke on my doka!but if I wiggle the selector the BU lights come on sorta so just a minor adjustment perfect :D

randr Mon Dec 20, 2010 12:20 am

Well not enough cleaning yet because it still won't start but will do it in the daylight the right way, just a little manic at this point.

It's the small stuff sweating me. Since the battery is cherry and it is getting fuel and the starter seems fine.

randr Mon Dec 20, 2010 12:59 am

OK not the ignition switch will check the neutral switch and/or starter in the AM.

Aloha & Good night

nod7 Mon Dec 20, 2010 12:13 pm

Oh, great post. I just recenlty put this issue on my to-do list because my backup lights don't come on unless you get the shifter perfectly into position. Now I have some detailed instructions on the isse.


Beygon Mon Dec 20, 2010 1:14 pm

Did this a couple weeks ago, bought both parts from VanCafe, no cookies?, it took about half an hour to do it, didn't take the cover completely off, just raised it, pried out the small piece, screwed the white piece in and plugged in the connectors. I did it just because the back up lights weren't working and both parts I took out had a lot of wear on them. Everything worked the first time, somethng new for me.

freakmonk Thu Feb 17, 2011 12:43 pm

Thanks Deprivation for the info. I've been having a problem starting my 90 auto gl. I noticed when I wiggle the shifter or move it forcefully into park it would start. I just removed the housing and disconnected/reconnected the wires on the neutral switch (battery disconnected of course) and she started up the first turn of the key. I guess the friction cleaned the contact points. Thanks.

davideric9 Sun Dec 23, 2012 10:40 am

I'm installing a new neutral safety switch and selector contact, confused about the lubrication, the grease. Seems like the old ones have a layer of grease on them. Di-electric grease is non-conductive so wouldn't this act as an insulator and cause a bad electrical connection? Should these parts be installed dry? What about lithium grease?

randywebb Sun Dec 23, 2012 6:35 pm

Di-electric grease should get wiped form the contact area -- that is how it works, tho I have heard not to use it on moving parts...

does the Bentley say to use it on this sliding contact?

you might try wiping it to ensure there is no more than a thin layer, then test continuity

do not use lithium grease

Powered by phpBB © 2001, 2005 phpBB Group