Engine Auxiliary Water Pump, no power

[backyardbill]

2006 XC90 4.4L, all options except Nav., 180k miles, runs near perfect except for the heater problem.

Gentlemen, Ladies,

This problem was discovered about a month ago when my wife reported that there was no heat in the passenger compartment. The ECC was set on high temp selected on driver side and passenger side.
This is what has been done to date:
1. Connect Vida 2014D, read codes. No codes related to the climate control or cooling system.
2. Check all functions of the CCM: blower (fan), temp selectors, automatic mode, all other modes. OK. A/C works fine.
3. Remove and test the temperature thermistor in the CCM and compare it to a new NTC 10 kΩ @ 25°C specs (NTC Thermistor Characteristics Curve). Same. Reinstall the thermistor. Check the thermistor fan. It works.
4. Note: engine thermostat and coolant was replaced Aug 2021. System was flushed. Engine reaches middle of dash gauge, normal.
5. KOER, warmed up, coolant hoses on firewall (to heater core), stay cool until the car is driving for 15-20 minutes, then begin to warm up to 60-70 °F. This is when its 25-30 °F outside.
6. Check the coolant pump (in left front fender well), not running. Check + voltage to pump: no voltage. Check ground wire: no ground.
7. Flush the heater core just in case there is blockage. Clamped the inlet and outlet hoses before removing. I used the boiling water method to flush. Add Prestone coolant flush to heater core. Reflushed the core. Used compressed air to blow out the core (through the inlet port first). Very little crud came out. Reversed the test hoses and repeated the flush process. Some crud came out the inlet port with the liquid. Blast repeatedly with compressed air and it burped up a wad of crud. Reinstall coolant hoses. Top up lost coolant.
8. KOER, same results as step 5.
9. Test the coolant pump operation: disconnect the plug from pump. Hot wire the pump to the battery + and ground – in the engine compartment. The pump works as it should. Leave it hot wired. KOER. Within 60 seconds the air at the vents in the car went to 110 °F!
My Vida 2014D doesn’t have wiring diagrams. And Vida didn’t provide any real help in explaining how the pump gets turned on and off as conditions change.
I searched for hours trying to find a wiring diagram that would reveal where the 2 wires to the pump come from, BCM, ECM, ???. The + wire is black. The – wire is light gray with red stripe.
Any help would be greatly appreciated.

[RickHaleParker]

My Vida 2014D doesn’t have wiring diagrams.

The Volvo Electrical Wiring Diagrams (EWD) are a separate disk.
Google Volvo EWD 2014D or you can go here and get just the one you need.

[ggleavitt]

http://vidaresources.volvocars.biz/ewd/ ... 998202.pdf , 2007 EWD copy direct from Volvo.

Electrical coolant pump powers off CEM B:14 via 5 amp fuse F20.