Location of 1993 aux water pump

[jwells2]

I'm trying to find the aux water pump on my 1993 500SL, if it has one.
The CCU is not functioning properly and I've read that it could be caused by a bad aux water pump. I want to check out the aux water pump before spending the big bucks on a CCU.

[speace]

It is under the cover near the passenger side hood hinge. Raise the hood to the fully-upright position and remove the 5 screws that secure the cover. You will see it close to the strut tower.

Oh, and if you need a CCU, I recommend ProgRama.

www.programainc.com

[jwells2]

Thanks, speace.

I looked there and what I found looked like the mono valve. But I'm still looking.

[speace]

Originally Posted by jwells2

Thanks, speace.

I looked there and what I found looked like the mono valve. But I'm still looking.

If the pic is the wrong thing, then ALLDATADIY is wrong...

In the official MB schematic of the CCU wiring, item M13 is labeled "Coolant Circulation Pump"

The wires on the pump should be:
Pin1=BKPKVT (BLACK/PINK/VIOLET?) (Hot wire/power source)
Pin2=BNGN (BROWN/GREEN?) (Gets grounded by the CCU to enggage)

This hot wire/power source comes from pin 20 of the CCU which also provides power to the "Y19 Monovalve", the "Y11 Switchover valve block" and the "B10/4 in-car temperature sensor fan."

The monovalve will have the same BKPKVT wire on pin 1, but pin 2 will be BNRD, so I presume that would be Brown/Red.

What are your wire colors? Perhaps that will confirm what you are seeing!

[Roncallo]

This is it on a a 1996 and I have one available on my E-bay store. The valve is on top the pump is the motor down below the valve.