Reverse Lights Won't Turn On - 1970 220d

[amt230]

Hi all - I've got a new problem that just popped up. Recently my reverse lights seemed to only be turning on when I entered reverse from N (not from P). Now, I noticed when someone else was reparking the car that they are not coming on at all. Other other lights are in working order, and fuses appear to be fine. I assume this has to do with whatever physically engages the light when you shift the car into gear. Any suggestions? Thanks!

[Govert]

The Neutral Safety Switch on your automatic transmission is faulty. It doubles as a switch to turn the reverse lights on. It is located on the automatic transmission, where the axle of the shift lever goes into the transmission (shift lever in the car > connected with a rod > shift lever on the transmission).

Sometimes adjusting it is enough.

[Tomguy]

If your NSS looks like this or is similar you may be able to just clean it up.
I've since done this same thing on my Jeep & saved money there, as well!

http://www.peachparts.com/Wikka/W108NeutralSafetySwitch

[Pooka]

If you have never worked on a NSS before then there is something to be aware of: They must be adjusted into position. This is not hard, but it can be time consuming.

If you take the switch off to clean the contacts, which is likely all it needs, then bench test it with a voltmeter to make sure it is working before you re-install it. That way if you car will not start you will not assume you have just wrecked everything, and you will know that you have to just make a slight adjustment in the position of how the switch is mounted.

This could also be something as simple as a wire coming loose from one of the connections to the switch. You will not know until you crawl under there and eyeball it.

The bottom line.... This is a simple repair, but it can drive you nuts trying to get that thing into proper adjustment.

And then there are times when you get it right the first time around. You will not know until you get in there.

[amt230]

Very helpful posts guys.

Since this is my first time working on one of these things, how do you access? Anyone have a picture of one in place (since I'm not around my car right now)?

I was recently working on the dash and adjusted the cable attached to the gear marker on the dash (it was previously reading as between gears and driving me crazy). I suspect that adjustment knocked the adjustment of the NSS out of wack, so I may just be able to adjust and not repair.

Assuming it does just need an adjustment, is that something that can be done when it is mounted, or do I still need to remove? Where is the adjustment tab when it is mounted?

Thanks!

[meltedpanda]

you may be correct, shift linkage may need adjusting, sometimes the rubber bushings that are intergral to the shift linkages fall out. If your car is starting in park it may not be the NSS , but rather not enough travel in the linkage. 'Because you made adjustments to your linkage you now have two possible issues. Eliminate them one at a time
You may need to get under the car to fully appreciate how the shifting works as it relates to the NSS
The NSS sits along side the tranny as does some /most of the adjustments for the shift travel

[amt230]

When I reparked the car tonight, I noticed that the reverse lights would flick on for a slight moment when putting the car back into park. So, it is likely not a complete fail of the NSS, just some adjusting along the line.

I don't want to adjust the shift linkages since they are connected to the gear marker in the instrument panel and I finally have that operating accurately. So, can I just compensate for it by adjusting at the other end at the NSS?

I guess I'm still not understanding how to adjust the NSS. But, I suppose I'll just need to get under the car to figure that out. That will have to wait until the weekend since it's dark by the time I get home and I don't have a garage!

Thanks!

[meltedpanda]

IIRC there are adjustments of the linkages under the car by the NSS