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heater circulation pump

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syncro_G
Posts: 823

heater circulation pump

Post#1 » Wed Nov 11, 2009 9:02 pm

I'm putting the finishing touches on my engine swap - still a few days of work left.

I have a question about the heater circulation pump. I had one previously with the webasto but all of that came out as a unit in transition from gas to diesel. I was thinking I'd skip adding a pump but Steve Smith has one and I don't want to be out done ;)

I have wiring diagrams for the 280GE and for the 300GD but don't see any reference to it. It's also missing from the donor 300TD wiring diagrams.

Here's my assumption:
Running power is fed to switch on the heater valve.
This in turn powers (directly or via relay?) the circulation pump.

So I assume that with engine on and heater valve open, pump is running.

Am I thinking it out correctly?
Do I need a relay to power the pump?

-Thanks, Christian

User avatar
syncro_G
Posts: 823

Re: heater circulation pump

Post#2 » Wed Nov 11, 2009 10:57 pm

Ah, just found my answer here:

http://pointedthree.com/disc/forums/sho ... =1#M104532

So yes, pump is on when both the heater valve is open (micro switch on valve) and ignition is on.
and power is controlled via a relay.

Thanks guys!

User avatar
syncro_G
Posts: 823

Re: heater circulation pump

Post#3 » Thu Nov 12, 2009 10:41 am

because the diesels idle at lower RPM - at which there's not enough flow to route water to the cabin heat. The donor car had it (without a webasto) and it appears that 300GD's with winter package had it.

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