auxiliary water pump wiring - Page 2 - PeachParts Mercedes-Benz Forum

Usaguy · #16 02-08-2020, 12:48 PM

Quote:

Originally Posted by jdere31760

Thanks guys for all the info.
Should I look into my ACC unit to see why the black wire is grounded or should I just replace the ACC? Sometimes when I am warming up the 300D, the ACC unit starts to rattle and after a few minutes, it stops.
I am also thinking I can just bypass the ACC and power up the auxiliary pump since it's not seized but I will need to find another circuit to tap into.
It's unbelievable how many items on this car still don't work or is leaking, I have been trying to solve one issue after another.

brown wire is grounded when you look at page 2 of this diagram:

https://www.startekinfo.com/StarTek/outside/12265/disc_2/program/ETM/123%20turbodiesel_2.pdf

I had my aux pump disconnected altogether at one time and the heat was great (240D and other manual climate cars don't have it).

What usually goes on this system is the monovalve will start closing at higher engine rpm

You can also protect your acc unit by running the aux pump through a relay and a separate fuse

1983 300CD · #17 02-08-2020, 02:18 PM

The pushbutton climate control unit in your dash sometimes rattles?

If you do end up with a working OE setup add a 1 Amp fuse in-line next to the pump. A modern blade fuse is better overall especially in that location.

jdere31760 · #18 02-09-2020, 11:15 AM

Quote:

Originally Posted by 1983 300CD

The pushbutton climate control unit in your dash sometimes rattles?

If you do end up with a working OE setup add a 1 Amp fuse in-line next to the pump. A modern blade fuse is better overall especially in that location.

Yes, 300CD, the pushbutton climate control rattles/vibrates especially when outdoor temps 25 degrees or less. Goes back to normal after car warms up.
I am going to install the in-line fuse.

jdere31760 · #19 05-15-2020, 08:51 PM

Quote:

Originally Posted by jdere31760

Yes, 300CD, the pushbutton climate control rattles/vibrates especially when outdoor temps 25 degrees or less. Goes back to normal after car warms up.
I am going to install the in-line fuse.

Actually it's warmer outside and the climate control rattles for a few minutes.
It seems to be the relays toward the back of the unit. I bought another climate control unit and it also rattles for a few minutes at warm up.

rocky raccoon · #20 05-15-2020, 09:22 PM

My opinion is that you should unplug the aux water pump and bypass it with a piece of hose. It can only cause a problem.

I have done this on my 300CD and don't notice any difference in heating performance. In fact, I have removed the pump altogether and use the rubber mount as a convenient place to safely store the block heater cord.

jdere31760 · #21 05-16-2020, 06:09 AM

Quote:

Originally Posted by rocky raccoon

My opinion is that you should unplug the aux water pump and bypass it with a piece of hose. It can only cause a problem.

I have done this on my 300CD and don't notice any difference in heating performance. In fact, I have removed the pump altogether and use the rubber mount as a convenient place to safely store the block heater cord.

Ok thanks Rocky!