Are your backup lights working?

[jbach36]

Much to my surprise, a friend of mine told me that my backup lights weren't working. I thought my dashboard "lamp out" light would have come on, but it's not on.

So I went and replaced a bulb today, and ..... no backup lights.

I stopped by a service station, he said there's a "backup switch" on the transmission, that when you put it in reverse, it tells the backup lights to come on. Since it's not telling the backup lights to come on, that's why my dashboard indicator is not coming on. The bulbs are probably fine, it's the switch that's messed up.

Where is this switch, and how hard to change? He thought it was a breeze to do. I searched the forum, but didn't find anything on this subject.

Thanks,

Jeff 1991 300d, 147k

[pawoSD]

The switch is on the side of the transmission by the linkages, and it is not very easy to replace.

[79Mercy]

Search "Neutral Safety Switch" or NSS.

[poppajim]

You are forgetting one other item. THE FUSE. That took care of mine.

[jbach36]

Originally Posted by poppajim

You are forgetting one other item. THE FUSE. That took care of mine.

I'll have to take a look at the fuse for the backup lights, but I'm sure the fuse runs more than just that! Seems like other stuff would not have worked, as well.

[Diesel911]

As previously started the Nuetral Safety Switch and the Back Up Light Switch are combined together.
Let us know if there is a fuse or not.
I know that so far I have not read of a Fuse at least where it concerns the Neutral Safety Switch part of the Switch.

[Jeremy5848]

Based on my reading of the W124 schematics, the same would hold true for any of the lights monitored by the "Exterior Lamp Failure Monitoring Unit." If the switch that turns on the lamp fails or if its fuse dies, the lamp won't work and the monitoring circuit won't have a clue.

So much for "fail safe." This is a good lesson for all of us. Monitoring circuit or not, we need to look at the lights every once in a while to confirm that they are working.

Jeremy

[MBeige]

Since I park backwards when I get home, I check the rear lights the next day by way of the wall illumination as I select different gears.

But one time I realized from a reflection in the grille of a car behind me, that one of the brake lights was out (I have the brake light mod, which includes the inboard lights with the brakes). Back then I thought the light off the wall seemed a bit dim, but I attributed that to more ambient light.

[jbach36]

I checked the fuse again, it's fine, plus it runs the horn, and a bunch of other stuff, so all those other things are working.

The car starts in reverse, but will not start in drive. Does that mean the neutral safety switch is defective?

jeff

[layback40]

Jeff,
You will probably find that its a simple adjustment. It needs moving a little, the switch is seeing reverse as neutral.

[fruitcakesa]

My NSS was cracked, the elec connector was sketchy and the whole thing was packed with crud.
It is not difficult to replace on a 123.

[Sev]

that's why you don't replace it by itself: you do the front flex disc, center support bearing, and tranny mount at the same time thereby combining labor