1990 Toyota Pickup 6 cyl Four Wheel Drive Manual 250, 00 miles
We posted an earlier question about having heater problems in the toyota - air blows fine, no heat, switch is fine, thermostate fine and we checked both hoses as suggested by you previously and both are hot. Where do we go now? Is there a switch under the dash? Lost - not sure what to do now.
It means the temperature blend door in the heater plenum is stuck, or the door actator is no good. This is the black box under the dash that the heat blows out of, your actuator is probably vacuum operated, and the servo may have a bad diaphram(not holding vac).