Aux pump relay?
 

Hi. On a 1984 300D Turbo can anyone tell me where the relay (if there is one) for the Aux water pump is located.
Direct 12V to the pump makes it run OK.
New (used) heater control unit works all the right things but no heat.
Thanks

The relay for the aux water pump is inside the pushbutton unit.

Thanks Tango. ? behind the unit or inside the plastic unit case. The wiring diagram shows a temperature switch and a vacuum switch in the supply line to the Aux. motor. Do you know where these items are located on the engine?
Thanks for your help

Inside. It's the K-1 relay, one of four. But the few that I have seen were not labeled.

My schematic does not agree with that.

If you have no heat at all, the problem probably involves more than just the aux water pump. Unless the pump happens to be completely obstructed.

Removed the Aux pump, bench test. Runs well, quite, smooth. Reinstall
Removed the ACC unit, fine sanded the relay points. Reinstall.
Now the pump runs but intermittent. When the pump runs I get heat, mono valve is working. Great!
Regarding the schematic. For the ACC unit only the power to the Aux pump seems very direct from the button switch to the motor.
BUT from the schematic for the whole car (1980) there are two switches. Is there a more current schematic?

Which physical relay on the board did you work on? I have been trying for some time to equate output loads to the various relays with little success.

Looking from the side of the board where the relays are visible, which of the "O"s below was the one for the aux pump? Thanks in advance.

I____O___O__O_____I
I_________O________I
I__________________I
I__________________I
~T~~T~~T~~T~~T

This might help.... That is if you can see it.

http://i252.photobucket.com/albums/h...123_Page_4.jpg





This is the wire harness diagram. #51 and 52 ends at the pump.


http://i252.photobucket.com/albums/h...123_Page_7.jpg

http://i252.photobucket.com/albums/h...123_Page_8.jpg



.

1980 still used the servo, while the 1984 does not. You need to look at a 1984 schematic.

If you're not getting any heat, the problem isn't the aux pump because if it does not work you get reduced heat but you still get heat. When I unplugged my pump until I got it fused, I noticed a difference but it was pretty minimal, only enough to make a difference in the dead of winter.

I just cleaned the contact points of all 4 relays

I have exact same problem. No power to aux pump... and like you said, direst power to pump makes it work.

http://www.peachparts.com/shopforum/showthread.php?t=263066

So there is a relay to this pump???? Help!!

Dave!!!

Bryan!!!!

Jimmy!!!

Roy!!!!

sanding between the relay contacts fixed mine

If you do sand the contacts, using dielectric grease on them before re-attaching them will help with the conductivity and prevent corrosion, ensuring a more reliable and long lasting connection.

TB, where is this relay that you tweeked??

if you take apart the climate control unit youll find 4 relays. Hook up the ccu plugs and you be able to find the relay that is always switching on when the dial is on heat. That is the one. Take a screw driver and bridge the relay pads with a screw driver. If the pump starts you know its that relay. Sand the pads and put electrical grease like the poster above suggested.

I made a thread a few weeks ago about how i fixed mine