Aux water pump

[henrym3]

It’s not working, fairly new, I’ve put 12v to it and it runs. . Checked the power lead to pump and get 4.7v. Traced that back to IHKA module pin 9 and getting 4.7v. Is this repairable, could the previous pump which went bad and rattled loudly when removed and shaken have caused the problem. I’m not seeing a fuse for that circuit.. Have used a separate earth to check, same result. Any options or opinions gratefully accepted.

[Greydog]

Morning Henry
We are both going through the same issue, I ran a scan Aux Water Pump fault. Changed the pump (second hand item) same fault replacement pump runs with 12v applied, original pump intermittent (runs if moved) so currently not tested voltage yet only that power is there but I suspect it will be similar to yours.

More Digging needed

Dave

[henrym3]

I also have the additional problem that on occasions I’m not getting heat on the drivers side, if revved it will come on and stay working fine for the duration of the journey. So not a blockage just a circulation problem. I’ve checked with diagnostics and the heater valves are working properly, don’t want to fiddle any more until aux pump is working because I think that’s at the route of the problem. I might just stick 12v on a switch to confirm. Don’t want to buy an IHKA module (second hand) to find it doesn’t fix the problem.

[Greydog]

I had the "no heat on the drivers side" problem but that went away when I changed the distribution valve/solenoid on the the inner wing.
My understanding of the Aux Water Pump was it circulated warm water before the main stat opened to give warm air in the cabin ahead of full operating temp being reached.

God save us from "clever designers"