12-05-2017, 10:24 PM
I assume the evaporator fan provides the air flow for the heater.
Does the evap fan run in the heat mode?
Is the evap coil clean, allowing air to flow?
The heater should have an air flow sensor. No air flow, no power to the heating elements. If you have airflow, check sensor.
The heating elements may have the voltage (V), amperage (I), or ohms (resistance) data marked on them.
If resistance is not provided divide voltage by amperage giving resistance. R= V/I.
Isolate each element from the rest of the circuitry and check the resistance to see if it is close to the value given or determined. If so the element is good.
OR
Isolate each element from the rest of the circuitry and jury rig a connection to the proper voltage. If it gets hot, it's good.
If the elements are good the control circuitry is not.
Good Luck
Tim
Does the evap fan run in the heat mode?
Is the evap coil clean, allowing air to flow?
The heater should have an air flow sensor. No air flow, no power to the heating elements. If you have airflow, check sensor.
The heating elements may have the voltage (V), amperage (I), or ohms (resistance) data marked on them.
If resistance is not provided divide voltage by amperage giving resistance. R= V/I.
Isolate each element from the rest of the circuitry and check the resistance to see if it is close to the value given or determined. If so the element is good.
OR
Isolate each element from the rest of the circuitry and jury rig a connection to the proper voltage. If it gets hot, it's good.
If the elements are good the control circuitry is not.
Good Luck
Tim