I'm putting an electric coolant pump into a modified Boxster. It's the same pump that a lot of BMWs use. What's the pin out/what connections are needed to make it run on a 12V switch?
I've got Red, Green, Yellow, Black.
I'm putting an electric coolant pump into a modified Boxster. It's the same pump that a lot of BMWs use. What's the pin out/what connections are needed to make it run on a 12V switch?
I've got Red, Green, Yellow, Black.
I think red/black is all you need. Ignore the other ones. Make sure there is water before running it.
looking at the pinout posted above, it sounds a lot like a relay. 1 red (+) and 4 black (-) are "load" power and ground, 2 would be switched B+ from a temp sensor or other "hey i want my pump to run now" and 3 would be ground for that switch circuit.
Bench test to save some possible aggravation.
And to go on ACs point, look at the implied wire sizes on the drawing. So make sure the pump gets plenty of current to spin.
In reply to alfadriver :
yes, bench test for sure. i forgot to mention that.
Yep, 2 wires didn't work. ***It's for a German car*** I tried 12v and ground on the control and got nothing. Pulled the back off to find about 5 chips and a couple capacitors. For now that project is shelved (and so is the pump). Reading some Bimmerfest, it seems these things are variable rate and computer driven with a high rate of failure.
May sort it out next month or may find a better solution.
Looks like it uses a PWM signal (because German). Useful information about 3 posts in on this thread.
https://www.miataturbo.net/engine-performance-56/bmw-pierburg-electric-waterpump-controller-69420/
Looks like you ground out pins 3 and 4, 12v+ to 1, the signal is probably 12v+, so if you jump power to pin 2 with everything else hooked up, the pump should run. You are wiring around the controller.
I just did a power antenna that was set up similar, the 12v+ feed fed the antenna down, 12v+ from radio made antenna raise.
In reply to benzbaronDaryn :
Problem lies in that the control wire is probably PWM so it may not see 12v even at wide open. I thought you could run them dumb (without the pwm) and they would just go full tilt but I don't know for sure.
You may not want it to run full tilt all the time. That could suck up a large amount of power from your alternator and engine.
Thanks for all the replies. Lots of good info for when I get back to it. Having a stand alone PWM controller could be the best way to go, better than my original thought of 12V feed with a constant output.
A PWM controller running based on engine temp would be a good setup. Event something as simple as 0% up to 120F and then ramping up to 100% at 180F would be worlds better than always-on or a mechanical pump.
In reply to GameboyRMH :
I agree, and I actually bet that 100% is way more than is ever needed.
And if it's anything like a mechanical pump, 100% might actually move less fluid than 80%!
I the flow is a concern you could look at it
https://killerglass.com/automotive/
I imagine there is some way to measure it too.
Will look tonight. IIRC one of the wires is signal IN from the DME and the other is signal OUT. The failure mode I have seen is that the pump does not send a good signal to the DME so the DME runs it full bore.
I'm following this for future ideas. As for the point of failure, my X3 with the N55 engine is on its third pump at just over 100k miles. The first one lasted about 80k, the second started to leak like it had a cracked housing after about 20k miles. FCP replaced that one on their warranty program.
One of the cool things the X3/BMW does is if you run it hard and shut it off before the turbo has a chance to cool down, it will run the pump for a while to save the turbo from your stupidity.
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