W108 Neutral Safety Switch

[w1083]

1972 280SE 3.5

I drove my car this weekend and noticed my reverse lights didn’t turn on. I had someone check the reverse lights as I went through the gears and they didn’t turn on at all. I’ve read if the Neutral Safety Switch is bad, the car wouldn’t start in Neutral either. I tried to start it in Neutral and it doesn’t crank but starts fine in Park. Is it safe to say the switch is bad? I do have an extra one I bought a while back when I realized they were discontinued.

I’ve owned the car 10yrs now and this is the first time I’ve had this issue. Is it as easy as getting under the car and swapping it out? Any help is appreciated.

[rumb]

The NSS is on the firewall below the brake master cylinder. Also check the bushing down by the trans, fuses and bulbs.

[w1083]

Originally Posted by rumb

The NSS is on the firewall below the brake master cylinder. Also check the bushing down by the trans, fuses and bulbs.

On my car, it's on the side of the transmission. I edited my post with my cars info.

[Tomguy]

If you have the cast aluminum switch you may be able to fix it for next to nothing.
https://www.peachparts.com/Wikka/W108NeutralSafetySwitch

[w1083]

I actually have the smaller, black plastic one.

[Tomguy]

I also rebuilt one for my XJ Jeep Cherokee that was plastic, I did need to use some JB plastic weld but I always have some on hand. Worst thing that happens is you take it apart and find out you can't fix it, can't break it any more than it's broken, right?
If you need to use the car you can bypass the pins for Park with a jumper wire, just be careful because it'll start in any gear if you do.

[Idle]

I had the problem of no back up lights on a 115 and found the switch to turn on the back up lights was in the shifter. I took off the shifter cover and discovered a small switch that the shift lever pushed against when it was in the reverse position.

I don't know if the 108s were the same but all you would have to do to find out is to pull off the shifter cover and look.

And my switch was not bad. It had just slipped out of position enough to keep it from closing. A small adjustment and Presto! Back up lights once more.

[250SE]

Mine wasn't working properly and I could start the car in gear. That was fun.

Just last week I replaced the steering box with a rebuilt unit and replaced all of the bushings and plastic pieces in the steering column and shifter column. The plastic adjusters for the neutral safety switch were cracked, so I replaced them with metal parts from MB Classic and adjusted them. Now it only starts in Park and Neutral.

[Treozen]

I have a '72 280 SEL 4.5 and about every third try, it wouldn't start in park - sometimes moving the shifter through all the gears would get it working again, other times it would start in neutral, but not always. It was a pain and I too had no back-up lights. The fix however was literally 5 minutes - I just adjusted the lever on the transmission....


Under the car, driver's side: The neutral safety switch is on the side of the transmission and there is a adjustment screw / nut on the side of the arm. This arm moves back and forth as you select gear and if the adjustment screw / nut is not tight, the neutral safety switch wont operate correctly. The adjustment nut on mine was about finger tight - so not tight at all really, and it could be moved independent of any actual shifting - which is why I was having this seemly random and intermittent no start in park. All I did was put the car in reverse (engine off) and move the lever until I could see the back-up lights come on (reflected on the garage door) and then I tightened up the nut - worked like a charm, completely resolved. I was all ready to buy a refurbished switch for 6 million dollars - but it was just a loose adjustment nut.