Radiator Drain Plug with leads

[ATL_Alan]

I have a three row radiator that was installed in my 1974 E9 about 20 years ago. The radiator drain plug has two male leads and there are wires in the car that connect to it. One of the leads decided to break off today while I was opening it to drain coolant. I'm guessing this was stock since I have the connecting wires; maybe my mechanic put it on the newer radiator back in 2001. I looked around RealOEM.com but don't see anything comparable. Questions:

1. What do the two leads control?
2. Does someone have a part number for this?

Thanks!

 

[sfdon]

Pic?
Look like this?

 

[ATL_Alan]

Sorry, should have sent some. Here's one from the side and one looking straight down on it. I tried to solder it back on but there's nothing to grab onto so it just melted some of the plastic.

 

[HB Chris]

It is the temp sensor that turns on the fan in front of radiator when A/C is off and car gets too hot. These were introduced in 74.

 

[sfdon]

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BMW 320i Coupe E21 2.0L L4 Auxiliary Fan Switch - 82 deg. C​

CHECK FITMENT

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$11.98
List price $66.91 , you save: $54.93

Quantity in Stock: 9 Ships on Monday

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[ATL_Alan]

Many thanks for the part ID, I'll order it today.

 

[TodB]

Don and his second (third?) job as a parts # provider. That’s for your help, Don, a couple of weeks back!

 

[jmackro]

It is the temp sensor that turns on the fan in front of radiator when A/C is off and car gets too hot. These were introduced in 74.

It's also fairly easy to retrofit this feature to earlier cars, though you won't get a lot of additional cooling with the stock pusher fan. Be sure to add a diode to the connection between the A/C compressor and the fan relay, so that when the car gets too hot, this switch doesn't turn on the A/C as well as the fan.

 

[ATL_Alan]

Hello all, installed the temp sensor in the radiator but the auxiliary fan is not coming on. The fan is a new SPAL fan and works because it comes on when I turn on the air conditioner.

Other than the temp sensor in the radiator, what controls that fan and what are the steps to troubleshoot?

Many thanks in advance for your help.

 

[Stevehose]

Hello all, installed the temp sensor in the radiator but the auxiliary fan is not coming on. The fan is a new SPAL fan and works because it comes on when I turn on the air conditioner.

Other than the temp sensor in the radiator, what controls that fan and what are the steps to troubleshoot?

Many thanks in advance for your help.

Jump the lead at the sensor to ground and see if the fan comes on while engine is on and ac off.