Up and under the dash, in the center console.
Heater core most likely needs serviced (or replaced)
10000.00
BIG JOB Get a manual from DISCOUNTAUTOREPAIRMANUALS.COM
Heater core changed three years ago,I changed Thermostat Heater still blows cool air.
bypass valve not opening
Regulator is in the alternator
275
It may need a heater core.
The heater core is located in the middle of the dash behind the center console. You have to take the console out to see the heater core.
I wouldn't think you could flush a heater core. you can flush a radiator. Heater core you would have to replace if it is leaking or stopped up
The hoses to the heater core can be disconnected under the hood. connect a water hose to the core, and try to flush the core to unclog it.
It would be bypassed by the mode door in the ducting under the dash. You may have have a problem with your mode door if your compressor is turning on when you select A/C. If the compressor clutch does not engage it is likely that there is an insufficient charge in the system, and you may have a leak.