Climate Control Module

[BsaThunder]

I have ordered a replacement (used of course) climate control module for my 1989 300ce.
I know my aux water pump is not operating and i am considering leaving this disconnected whilst i assess the response to the replacement climate controller.
My current controller does not activate the heater valves, so I get hot air all the time!
My question is whether:
1. leaving the aux pump unconnected will still allow the climate controller to operate its other functions unimpeded
2. Is the aux pump necessary at all in Tasmanian temperate conditions, my understanding being its function is to increase heating ability when the engine is idling?

Hoping for some sound advice for my first interaction on this forum

[John Green]

Two points to help you:

1) with the aux pump not working you will have minimal or no flow as the seized impeller creates a blockage in the system.
2) the most common issue with hot all the time is that the diaphragm in the duo valve has split and allows coolant to pass though all the time. Maybe, you already have checked that there is an off/on signal going to the valve? If so ignore this point.

[BsaThunder]

Two points to help you:

1) with the aux pump not working you will have minimal or no flow as the seized impeller creates a blockage in the system.
2) the most common issue with hot all the time is that the diaphragm in the duo valve has split and allows coolant to pass though all the time. Maybe, you already have checked that there is an off/on signal going to the valve? If so ignore this point.

Thanks for your reply John.
I have checked and cleaned the duo valves and when hard wired to a 12v source they stop the flow of hot water allowing my ac to provide cold air from all vents.

Hence my assumption the climate control module is not sending a signal to the duo valves.
There does seem to be plenty of water passing through the aux pump as the heating functions operate well. I am assuming if the pump was blocked I would not be getting heat??