Does anyone know what controls the airpump relay? I am doing some troubleshooting on the airpump system and I found that there is always voltage present on the control relay solenoid terminals when the ignition is on. Is the fan supposed to turn off within a certain time after the engine is started and what sensor(s) control the power to the fan relay solenoid? I couldn't afford the zillion dollar electrical manual so I am hoping someone has been down the same road before. THANKS!

V70s 1999 don't have air pumps (USA). Most relays in the Volvo have power and the control circuit of the relay allows the power to the load. In the case of an air pump (not used after 1998) the ECM controls the relay.
--
Rich K.

Sorry I listed the wrong year. The car is a 1998. OK, the ECU controls the airpump relay. When does the air pump shut down after the engine is started, is it the same time as the exhuast check valve closes? From what I can tell on my car, the relay seems to be energized whenever the engine is running. I would appreciate whatever additional input you could provide.

When you start the car and it's cold enough (ECT sensor input to the ECM) the air pump will run because the ECM grounds the relay (that has power all the time) and the air pump will run, at the same time, the ECM grounds the SAS (secondary air system (air pump))control valve that will allow the engine vacuum to open the SAS valve so the air pump discharge can be dumped into the exhaust manifold. The air pump will run for a max of 2 minutes. If the car is already warmed up the air pump is not suppose to run. I have seen the air pump relay stuck shut and the air pump would run regardless, and would drain the battery when the ignition is off. The below link has a write up on the air pump.

http://www.volvospeed.com/bay13.htm
--
Rich K.