1981 300sd
 

I have a 300sd and the speedometer is not working. Please help! Here's what i can tell you. Wasn't working when i bought the car. Car sat for long time. On rare occasions when I hit a bump it starts working for a little while (few minutes). Everything else in the dash works. Checked ground behind dash and its good. I noticed there are three wire connections on the trans. Can someone tell me which one is for the speedo? Looking from the front of the car there is a bigger plug on the right side. I noticed a smaller one that only had one wire going to it toward the top back right side. I also noticed another lead going to the left back side. I already tried a dash with a working speedo and it doesn't work. I'm assuming since it sometimes starts to work when i hit a bump it is a loose connection somewhere. Thanks in advance for any help.

Qustion about new sending unit.
 

For speedometer sensor on trans. Can i splice the new sensor into the old wire harness so i dont have to tear apart half the inside of my car, Thanks!

cant find new sensor
 

Help! I cant find this part for my car. Vin# WDBCB20AXBB002937. Original part number 005 542 2217. It looks like the one in the mercedes van. This is the part i found but it is not the right one: 0105422217.

This is the one from my car

This is the one from my car