BMW 1994 528I temperature sensor/sender [Archive] - Bimmerfest - BMW Forums

: BMW 1994 528I temperature sensor/sender

10-06-2009, 02:52 PM
Hello Knowlageble people of bimmerfest
I just doing some reading on old post, and cant fine a acurate answer. I am wandering if any one can help me?
I have a 1994 525I that was over heating and after reading some info here and there, I want to change all of the temperature sensor/sender but my problem is that there are 2 on the engine head that have same plug (12621747281 black & 13621709966 blue) but looking at the plug itself one have 2 wires coming from the engine harness and the other only one. I was wandering if you can determent witch plug goes where? I appreciate in advance for all your help and trouble

10-06-2009, 04:25 PM
If it is overheating you have other issues. Have you replaced the water pump or thermostat?

10-06-2009, 10:09 PM
Yes I replace them both pump and thermostat, but beside overheating my temp gauge is acting up; for instance once I put the key on the ignition move it over but not all the way to hit the star the temp gauge is all the way to the hot side and then once I start the car it drop all the way down to cool and it doesn't move even after the car is overheating.
So I figure since the car is overheating (it probably need a good bleed) but I get there one I can read my temp gauge. Now if you be nice and take a look at the amount of wires that are coming into your black or blue sensor I can properly install mine.

Thank You

10-07-2009, 05:55 AM
The blue is the fwd plug that is the coolant temp sensor. The other one is the Temp Gauge sender

10-07-2009, 10:47 AM
Thanks for the reply, but still don't know if the plug with 2 wires goes to the sender (black part # 12621747281) or the plug with only one wire. Cud you please verified on your car?

Thank You

10-07-2009, 11:01 AM
Both look black to me.

10-07-2009, 12:55 PM
exactly both plug are same with the exception one have two wires and the other one, the sender itself are color coded

10-07-2009, 07:25 PM
Perhaps the blue marker on the wire is the tip off? I am only guessing.

10-07-2009, 07:43 PM
Yes, the blue marker goes to the fwd blue sensor.

10-14-2009, 02:17 AM
As you can see from the pictures of my wire plugs, I only have one wire going to the temp sender plug, I have try checking out the connections to the temp gauge but no look so far
I also replace the thermostat sender/sensor (both) and still have same problem; my temp gauge don't work.
I did the diagnosis test to the instrument cluster and everything looks fine.
Now I am looking at this wire-ring diagram; if I am looking it correctly I see two separate wires going to the plug (.5 GE/WS and BR/GE)
I am wandering if my car is missing one wire there? Can some one look at there plug (for the black sender) and confirm that are two wires in there ?
I am relay frustrated right now, since everything I do let me to nothing so far.

Thank you

10-14-2009, 02:17 AM
Finally I found my problem, the mechanic that was fixing the car have switch the plug from the oil to the temp sender. After finding the pin layout to the engine plug connector (X20) I found that pin 11 & 12 are the temp gauge wireds and that pin 23 is the oil pressure switch (one wire)

10-14-2009, 11:16 AM
is it running cooler now that it is reading the right sensor? :)

10-14-2009, 04:11 PM
I think my problem with the over heating was due to an incorrect antifreeze flush done in the car previously. The black sender is only for the dash gauge, but I am very satisfied that finally found the problem