Does anyone know what the difference is between the 1 pin oil pressure sender used on the W126 and the 2 pin sender used on the W140? The W126 sender grounds through the oil filter housing. Does the W140 sensor use the 2nd pin for a ground, or is it a connection for the low oil pressure light in the cluster?

Thanks,

-J

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1991 350SDL. 230,000 miles (new motor @ 150,000). Blown head gasket

Tesla Model 3. 205,000 miles. Been to 48 states!
Past: A fleet of VW TDIs.... including a V10,a Dieselgate Passat, and 2 ECOdiesels.
2014 Cadillac ELR
2013 Fiat 500E.

Anyone have access to a wiring diagram for one of these later cars?

-J

__________________
1991 350SDL. 230,000 miles (new motor @ 150,000). Blown head gasket

Tesla Model 3. 205,000 miles. Been to 48 states!
Past: A fleet of VW TDIs.... including a V10,a Dieselgate Passat, and 2 ECOdiesels.
2014 Cadillac ELR
2013 Fiat 500E.

One is for oil press.light and one is for pressure gauge.
Newer W140 had one pin sender too.

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Mercedes W140, S350TD, 95.
Mercedes W140, S350, 92.
Porsche 944, 86 N/A.
Porsche 944, 85 N/A automatic.
Porsche 944, 84 N/A.
Porsche 944, 83 N/A.
Opel GT, 73.
Toyota Supra MA61,84.

Do you have a part number or year and model for the 2 pin oil pressure sender?

Thanks,
Sixto
87 300D

The part number is A0095420817. I found it by looking at the diagram for a W140 300SD, but it is used on many other models as well.



If the 2nd pin is for the low oil pressure light I will install this on my W126 and connect the 2nd pin to the low oil level light

-J

__________________
1991 350SDL. 230,000 miles (new motor @ 150,000). Blown head gasket

Tesla Model 3. 205,000 miles. Been to 48 states!
Past: A fleet of VW TDIs.... including a V10,a Dieselgate Passat, and 2 ECOdiesels.
2014 Cadillac ELR
2013 Fiat 500E.

I put something similar on a VW Beetle years ago but the low-pressure trip point was too low (~5psi) to be useful -- by the time it got that low you were dead anyway. Still, it would be interesting to get a measurement of the trip point.

As a comparison, my home-made installation trips at about 15psi. It doesn't come on in normal operation (might blink a couple of times at hot idle, until the ELR circuit brings the idle into spec). If it does come on while driving I immediately know I've got a problem yet there's still enough pressure to give me a couple of seconds to safely shut down the engine.

Jeremy

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"Buster" in the '95

Our all-Diesel family
1996 E300D (W210) . .338,000 miles Wife's car
2005 E320 CDI . . 113,000 miles My car
Santa Rosa population 176,762 (2022)
Total. . . . . . . . . . . . 627,762
"Oh lord won't you buy me a Mercedes Benz."
-- Janis Joplin, October 1, 1970

I'll pick one up and find out. I need to replace my sender anyway and the price difference between the one with the switch and without is minimal.

-J

__________________
1991 350SDL. 230,000 miles (new motor @ 150,000). Blown head gasket

Tesla Model 3. 205,000 miles. Been to 48 states!
Past: A fleet of VW TDIs.... including a V10,a Dieselgate Passat, and 2 ECOdiesels.
2014 Cadillac ELR
2013 Fiat 500E.