Neutral Safety Switch R&R - 126
 

Just replaced the NSS on my 85 Euro 500SEC. Car would not start in P at first, then only in N, then not at all. Had the idea at first that the switch might out of adjustment or just be dirty after "250K" and thought I'd just pop it out and clean it. Found it to be filled with white oxide powder from corrosion and one contact completely gone. Here's is the process.

1) The switch is located on the LH side of the tranny on the selector shaft sandwiched between the housing and the tunnel. About 3 inches to work in.

2) It is MB PN 000 545 53 06 available on line for about $73.18 including shipping.

3) To remove the switch jack up the front end as high as possible and secure with jack stands and chocks as you will place the lever in N at some time during the process.

4) Clean the area as best you can before starting.

5) Unlock the electrical connector to the switch by rotating the white collar CCW on the switch body. Gently pry the connector from the switch.

6) Tools: Common Srewdriver, 1/4 drive 10MM socket and 2" extension, 10MM combination wrench and a magnet on an extension.

7) With the shift selector in N, loosen the 10 MM bolt, nut and washer holding the shift lever on the tranny to the selector shaft. Remove the bolt entirely because it fits in a detent. Slide ther lever off the shaft. Notice the arm on the switch has a protrusion that fits into the lever.

8) Remove the 2 10MM bolts and washers holding the switch to the tranny.

9) Slide the switch off the shaft.

10) The switch is riveted together but if your curious it's worth drilling out the rivets just to see how complex this thing is. Remember it has contacts for N, P and also operates your back up lights.

11) You will also notice a hole in the lever on the switch that lines up with a hole in the switch housing when the unit is in N as it should be now. Remember this when putting the new one in. An allen wrench can be used to check the position and who knows maybe yours is just out of adjustment. The screw holes on the switch do allow for some adjustment.

12) To install the new switch, set the plastic switch lever to it's N position, assure the car is still in N and simply slip the switch back onto the shaft.

13) Place the lever back on the shaft and make sure the protrusion fits into the slot on the lever. Double check the postion of the switch with the allen wrench inserted in the hole and install the bolt, nut and washer holding the lever to the shaft. Next using your very skinny fingers or the "magnet on a stick" place the bolts in the mounting holes and tighten.

14) Reinstall the electrical connector, rotate the white collar to lock it in place. With the car still on stands (Just in case), place the shift selector in P and start the car.

The pics I have of the switch are too large to upload here but you can write and I'll be glad to send a couple.

Excalibur2005 said: It is MB PN 000 545 53 06 available on line for about $73.18 including shipping.
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Fastlane, who sponsors this website, has the switch priced at $46.00.........try them first next time.

Darn....!
 

And that's $30 I could have spent on Heineken to celebrate my successful repair with! Thanks for the feedback guys!