Witchboard Posted September 29, 2021 Share Posted September 29, 2021 I'm wiring up my electric fan in the Z, using the Ford Taurus fan. My question is about the BMW temperature switch. Mine has 3 wires, I presume a high temp, low temp and ground. I wasn't sure which wire was which, so I started my car warmed it up and put my multi-meter across all the connections. I'm presuming it would just close the circuit, but I'm not getting any continuity across any of the pins. I started it back up and basically red lined it on temp and still nothing. Is my understanding how this thing works incorrect? Do I need to ground the housing? Do I have a bad sensor? Quote Link to comment Share on other sites More sharing options...
lowrider Posted September 30, 2021 Share Posted September 30, 2021 You are correct in your assumption that one leg is the signal ground and the other two pins are the high and low signals. There should be continuity across the common pin to the low pin at its switching temp as well as the high at its switching temperature. If you aren't getting continuity across any of the pins it might be fair to say the sensor is bad. Quote Link to comment Share on other sites More sharing options...
Witchboard Posted September 30, 2021 Author Share Posted September 30, 2021 Bummer. Thanks. At least they aren't that expensive. Might as well buy a new one rather than pull another from LKQ. Quote Link to comment Share on other sites More sharing options...
Witchboard Posted October 6, 2021 Author Share Posted October 6, 2021 (edited) Got my new sensor in and it's working, but I can't figure out the pinout. I ran the car up to temp and they all 3 seem to make continuity at the same time. I get that 15 degrees isn't a lot when you're around 200, but I would have thought I'd at least be able to figure which is ground. Doesn't seem to matter which two I connect, they all beep my multi-meter. Anybody know the pinout of this? I've tried searching online, but can't seem to find one. I checked the forum, but maybe I'm not looking for the right key words. Edited October 6, 2021 by Witchboard Quote Link to comment Share on other sites More sharing options...
NewZed Posted October 7, 2021 Share Posted October 7, 2021 Try to find a wiring diagram of a BMW that uses the switch/sensor. Maybe the BMW boards. Quote Link to comment Share on other sites More sharing options...
Witchboard Posted October 8, 2021 Author Share Posted October 8, 2021 Okay, I found it. Just for future reference, the brown is ground, black is high and purple is low. I tested it just to make sure this evening. I turned off the engine before it reached temp and let it creep up while shut off with my multi-meter connected. Should be able to finish up my wiring tomorrow. Had to come in because the mosquitoes were trying to carry me away. Quote Link to comment Share on other sites More sharing options...
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