I'm not sure exactly which year models have a combined pump/valve unit and which have seperate units, I usually just look at the car.

Have a look and see if you have a combined or seperate pump/valve units.

Your next check is to run the engine upto operating temp (with climate control on min temp, no a/c. Put one hand on each side of the heater valve. get someone else to turn the heater temp on full (with engine running) and see what happens. It should get hot.

The 3 remaining possibilities are faulty control unit, a problem with the ventilation air blend system (blend hot and cold air) and a faulty heater valve.

__________________
Alex.

MB Tech
Sydney, Australia
Volvo 122S
W201 190D 2.5 manual
W202 C240
W203 C32