Disassembling Connector for Radiator Temp. Sensor?

[JayZ3]

I discovered that I have one of the Z3s whose radiator temperature switch connector was mis-wired from the factory - no radiator-controlled low speed fan. I have been trying to disassemble the connector so that I can swap the pins around (see here https://www.bimmerforums.com/forum/s...onfusion/page2 and here https://www.bimmerforums.com/forum/s...ic-fan-failure), but I can't figure out how to get it apart. The connector, aside from the pins, seems to have four pieces: a black outer housing, a black three pin inner housing, a white plastic piece on the inner housing, and a gray rubber water-proof ring. I presume that I need to separate the inner housing from the outer, remove the white piece, and depress the tabs on the pins; but I haven't been able to figure out how to get the pieces apart. So far, I have broken nothing on the connector in my efforts, and since I can't find the part number on RealOEM, I'd like to keep it that way.

[deni2s]

since I can't find the part number on RealOEM

Enter your vin in realoem and search for "DOUBLE TEMPERATURE SWITCH", you will find it under radiator sections. Not giving you the part #, as there were two different versions (but my guess is you have #61318363677).

[JayZ3]

Deni2s, Thanks for the reply: that part number is the switch the connector plugs into. My trouble is getting the connector apart so that I can move the pins to the correct position.

[JayZ3]

Gently working on nineteen-year old, heat-embrittled plastic, the solution is to 1) Pry the lock tab slightly up on the circumference of the outer sleeve. 2) Slide the outer sleeve down onto the wiring harness (my mistake had been trying to slide it off the connector). 3) Gently work the barbs on the white plastic retainer off of the inner connector. 4) Depress the tabs on the pins and pull the wires out.


Result: Brown wire in the middle of the dual-temperature switch.

[gmushial]

Isn't what deni2s is saying is: if you can't raise the bridge, lower the water, ie, if you have one of the backwards connectors, then get a matching switch for that miswired connector?

Though didn't RandyW comment on this this last week, ie, the definition of the correct placement of the brown changed during the Z3 production?

CALLING RANDYW... your comments, please.

[BimmerBreaker]

Isn't what deni2s is saying is: if you can't raise the bridge, lower the water, ie, if you have one of the backwards connectors, then get a matching switch for that miswired connector?

Though didn't RandyW comment on this this last week, ie, the definition of the correct placement of the brown changed during the Z3 production?

CALLING RANDYW... your comments, please.

As I remember... the brown wire should always be in the middle but the numbering system on the harness changed, so it used to be in position 2 which was the middle until BMW changed the numbering system so that the middle became labelled as 3. This change caused some workers to install the brown wire in the wrong position.

[gmushial]

As I remember... the brown wire should always be in the middle but the numbering system on the harness changed, so it used to be in position 2 which was the middle until BMW changed the numbering system so that the middle became labelled as 3. This change caused some workers to install the brown wire in the wrong position.

But was there also a matching thermo-switch to match that... that's what it sounds like from above.

[Mr Bingley]

I discovered that I have one of the Z3s whose radiator temperature switch connector was mis-wired from the factory - no radiator-controlled low speed fan. I have been trying to disassemble the connector so that I can swap the pins around (see here https://www.bimmerforums.com/forum/s...onfusion/page2 and here https://www.bimmerforums.com/forum/s...ic-fan-failure), but I can't figure out how to get it apart. The connector, aside from the pins, seems to have four pieces: a black outer housing, a black three pin inner housing, a white plastic piece on the inner housing, and a gray rubber water-proof ring. I presume that I need to separate the inner housing from the outer, remove the white piece, and depress the tabs on the pins; but I haven't been able to figure out how to get the pieces apart. So far, I have broken nothing on the connector in my efforts, and since I can't find the part number on RealOEM, I'd like to keep it that way.

So I read through the linked threads and just became aware of the miss-wiring of the fan/temp switch from the factory issue. I figured I'd check my switch--build date 3/98. I got all excited thinking I might have this issue and never have known it--I can't recall ever seeing the fan come on at low speed. I got my flash light out and popped the hood and.....I'm color blind--they are all the same color to me--almost all wiring is the same color to me--I forgot. As far as I can tell all three wires are brown.

[rf900rkw]

There is no matching switch. There are two plugs, big and little. Both styles have the common on the center pin. On the ld big plug, the center pin was called #3. On the new style, it's #2.

[gmushial]

So I read through the linked threads and just became aware of the miss-wiring of the fan/temp switch from the factory issue. I figured I'd check my switch--build date 3/98. I got all excited thinking I might have this issue and never have known it--I can't recall ever seeing the fan come on at low speed. I got my flash light out and popped the hood and.....I'm color blind--they are all the same color to me--almost all wiring is the same color to me--I forgot. As far as I can tell all three wires are brown.

Take a picture and post it? ... I'm going to have explore mine also, in that I don't think I've ever heard the fan come on low... (8/98 build date).

[gmushial]

So: in the image from post #27 of https://www.bimmerforums.com/forum/s...onfusion/page2 the left and center wires need to be swapped?

[rf900rkw]

The image doesn't show connector orientation. At a minimum it will need the two swapped, but I suspect it needs all three. I just typed all of this up three days ago in a different thread the is still on the first page.

[gmushial]

The image doesn't show connector orientation. At a minimum it will need the two swapped, but I suspect it needs all three. I just typed all of this up three days ago in a different thread the is still on the first page.

ie, https://www.bimmerforums.com/forum/s...lete-Questions


edit: just checked mine (10/98 build) and the brown is in the middle :-)

[rf900rkw]

I corrected that thread and drew an ascii diagram. This is looking at the pin end of the connector, per BMW standard illustration.



B/Gn----------B/Gr
2-------------------3
---------1----------

Brown ^


vs


B/Gn---------B/Gr
3-----------------1
--------2---------
Brown



As you can see, the wire positions in physical space stayed the same. But the logical pin numbers changed. This is where production got bamboozled because they were told of one change, but not the other

[BimmerBreaker]

So I read through the linked threads and just became aware of the miss-wiring of the fan/temp switch from the factory issue. I figured I'd check my switch--build date 3/98. I got all excited thinking I might have this issue and never have known it--I can't recall ever seeing the fan come on at low speed. I got my flash light out and popped the hood and.....I'm color blind--they are all the same color to me--almost all wiring is the same color to me--I forgot. As far as I can tell all three wires are brown.

I just went out to look at my connector hoping that the non-ground wires would be differentiated by stripe width or something... one of them is striped, the brown and blue however are both solid.

[rf900rkw]

You might do better if you look at the correct plug. No blue wires at the temp switch.

[BimmerBreaker]

You might do better if you look at the correct plug. No blue wires at the temp switch.

I was looking at my E36 which I assumed was the same (that car is is far from original though). The wiring colors on my M coupe are black with a yellow stripe, brown in middle, then black with a green stripe.

[gmushial]

I just went out to look at my connector hoping that the non-ground wires would be differentiated by stripe width or something... one of them is striped, the brown and blue however are both solid.

On mine it took some wiping to get 200k miles of road grunge off... but yes: black/gray, brown, and black/green.

[JayZ3]

My build date, incorrectly wired, was 5/98.

I discovered the issue when diagnosing why my viscous fan was engaging on hot days while stuck in traffic (the temp. gauge never climbs above a tick past twelve). I tested the radiator switch connector by jumping the contacts, and brown to either of the other two engaged the fan at one of the two speeds. I then replaced the radiator temperature sensor, but no change. Suspecting that the fan clutch was failing in the engaged position, I decided to replace it; however, if I was going in for the fan clutch, it was also time to do belts, pulleys, thermostat, and water pump, but no change. That's when I discovered the thread about the mis-wired radiator switch connector. I put my old fan switch in boiling water and found that the first contacts that engage are the center and the top - entirely by-passing the brown on the bottom. I wasn't able to get the second position to engage (99 C), which should connect all three pins, but water boiling at Milwaukee altitude is only about 99 C; that may not be hot enough considering manufacturing tolerances for an advertised 91 C/99 C switch.

The curious part about all this is that even though I have corrected the fan switch wiring, replaced the radiator switch, installed a new 92 C thermostat and a Stewart water pump, and have a new fan clutch, nothing has changed. The viscous fan still comes on while stuck in traffic on hot days; and testing while parked, the viscous fan engages but the aux fan never comes on.

[Mr Bingley]

So I checked today, and the fan comes on whenever the air conditioning is turned on, and if I let it idle on a hot day. I believe this means the switch must be wired correctly. This is the first time I've turned the air on in a couple of years---works great despite my neglect. The water temp needle never gets past 12:00 on the gauge, and oil temps rarely go above 200° (it has a cooler), so I think it's good.

[deni2s]

So: in the image from post #27 of https://www.bimmerforums.com/forum/s...onfusion/page2 the left and center wires need to be swapped?

All three need to be swapped.

- - - Updated - - -

So I checked today, and the fan comes on whenever the air conditioning is turned on, and if I let it idle on a hot day. I believe this means the switch must be wired correctly.

Wrong. Air conditioning turns on with incorrect wiring too.

[JayZ3]

Yes, the low-speed fan comes on when the air is turned on even with incorrect wiring, but if the low-speed fan comes on while idling without the air-conditioning on, then the wiring must be correct.

[Bladecatcher]

So back to this fun subject...

How the hell DO you get this connector apart in order to get the wires into their correct positions?

I'm at a loss and really don't want to mutilate all of that plastic.

Sent from my SM-G920P using Tapatalk

[KeysCoupe]

What I do in a situation like this is I go to the U-Pull yard and start practicing on other BMWs. Break one or two apart, and find out how they fasten, then try to carefully extract wires to swap around on the next until you are confident enough to work on your own car.
-Donny