M119 B11/2 sensor question (92 400E)
 

Hi

Replaced the wiring harness on my 92 400E this weekend (the insulation on the wires was completly cracked). Everything went fine till I got to the B11/2 connector (4 pin round) when I noticed the harness connector is keyed but the temp sender is not:confused:

I checked the sensor with an ohm meter and found resistance on the pins diagonally (4.66 and 4.61Kohms temp was maybe 50F) So I figure it doesnt matter what orientation the connector is plugged in. Correct?

My real question is why did they use two seperate sensors? If both circuts read the same value wouldnt it have been better to have one sensor with two sets of wires?

Thanks
Paul

The 4 prong is two sensors in one base .. but they are both the same value, so there is no orientation .
The reason for two sensors is they run completely different
circuits , ie.-must be isolated...

What Arther said. I will just add that the connection to two thermistors are center symetric so there is no way you can connect it wrong. I went through it last year when I replaced the harness.

" center symetric " ...

I like that one ....

Thanks Arthur and Rafi,

Thanks for the confirmation of the symetry.

Two isolated circuts make sense. I hadn't really thought through what would happen to the reading if they were hooked up to seperate circuts.

On newer vehicles do they use one sensor and then convert the info to digital which any subsystem that needs temp can use? This would seem to reduce the number of sensors and connections which are possible failure points. Just curious since the level of electrinic complexity keeps increasing.

So my background is mechanical engineering not EE:)

Paul