Round 4 Pins Coolant Temperature Switch ? which way should I plug in?
 

Help me out Guys!
My 91 300se coolant temperature switch look old enough to replace , so after I installed a new one now I try to plug it back and don't know which direction it should be plug in:confused::confused: you know the round 4 pin one near the fire wall..please help..many thanks.

The two thermistors in that sensor are diagonally wired and of the same value, so you can plug it in any way and it will always be correct.

Thank you, that will help me alot cheeer:dancefool

I could swear it only plugs in one way....

No, either way is ok, it's not keyed.

From my manual:

4-pin engine coolant temperature
sensor (Bl l/2)
The engine coolant temperature sensor is a 4-
pin design. It integrates two separate
temperature sensors (NTC), which do not have
any electrical connection to the housing of the
engine coolant temperature sensor. One
temperature sensor is used for the distributor
ignition system and one for the CFI injection
system. The connector of the engine coolant
temperature sensor is designed so that it can be
plugged-in in any position.

Your assumption is incorrect.

You're Welcome....

Well then, I guess there's always a first time. :D ;) :P

Don't over-tighten the sensor when you install it.
See top item in image below.:rolleyes:
$ 50.00 down the drain plus another $ 50.00 to replace it.
Plus it wasn't simple getting the broken half out.:(

http://farm4.static.flickr.com/3377/...5d274bcd_o.jpg

That is why its a good idea to always use a torque wrench when putting in stuff like that. MB lists the proper nm measurements.