1980 300D.

I had a/c but no heat. Then a/c stopped working, too.

I just had the servo replaced as it was cracked and leaking.
There is still no heat. The tech thinks that the aux. pump needs to be replaced and this would fix the heat issue. (I assume he means aux water pump mentioned here). Does this make sense?

From reading the other threads I noticed that the aux water pump can be removed and that its function is to increase the amount of heat.
I have no heat at all and the a/c is iffy.

Where is the $75 aux water pump on mercedesshop?

If I decide to remove the aux pump, what kind of hose do I need to put as a replacement or should I just unplug it.

If I decide to replace the aux pump with a new pump is it a simple unplug and replace or does anything else need to be done before or after?

If the complete lack of heat has nothing to do with the aux pump, what is causing it?



I am also coming across this part called the "electric water pump" which looks very similar. Is it the same as an aux pump?
MBZ037173
MTC/Ronak Electric Water Pump
w/ auto climate control; 15mm hose connections; 13 inch long cable; w/ 15mm hose connections & 13 inch cable length; Packing SizeIECE; Qty Per Vehicle:1;