Chapter 4
Troubleshooting
loosen the hose clamp on the blower and slide it off of the combustion chamber. If the
there are no obstructions, the blower should turn freely. If the blower doesn't turn freely,
it needs to be replaced.
No
If the heater is running off trailer power, check the fuse supplying power to the
trailer. If the heater is running off the 110V standby, check that the extension cord is
properly plugged in. Also check the fuse in the circuit supplying power to the 110V
standby and the fuse in the 110V standby.
Problem B: The green indicator light comes on but the blower does not
run
Do you hear a faint clicking noise fifteen to thirty seconds after you turn up the
thermostat?
Yes
Focus your troubleshooting on the blower and the associated circuitry by
checking the following list of items:
1) Check that the two wires to the blower are firmly attached and there are no
obstructions in the blower. To check for obstructions, loosen the hose clamp on
the blower and slide it off of the combustion chamber. If there are no obstructions,
the blower should turn freely. If the blower doesn't turn freely, it needs to be
replaced.
2) Check the wiring connected to the wiring tray. Look for loose, corroded, or
damaged wiring especially at the power and fan terminals on the back of the
ignition module.
3) Remove the cover to the thermostat and check that the heater is receiving at least
11.0 VDC if hooked up to battery power and 14 VDC when powered by the 110V
standby. Voltage will not be this low unless there is a problem in the electrical
system between the heater and the vehicle or the battery is run down so much the
vehicle won't start. Start by looking for loose or corroded connections.
4) If none of the above solve the problem, remove the blower and connect it directly
to the battery. If the blower runs, the ignition relay should be replaced.
No
This indicates the sail switch is stuck open or the voltage to the heater is very low.
With the power to the heater off, check the resistance between the two terminals on the
sail switch (or on older models with three terminals the wires should be attached to the
the two terminals on the right side). If this resistance is less than 100 ohms or so the sail
switch is either stuck open or bad. Remove the blower and adjust the sail switch if it is
stuck. If it isn't stuck replace it.
If the sail switch wasn't the problem, either there is a bad connection in the wiring
supplying power to the heater or the device supplying power to the heater has significant
problems. If the heater is running off the 110V standby, the 110V standby may need to be
serviced. If not, check the condition of the vehicle battery.
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