VEHICLE COMPARTMENT HEATER MALFUNCTIONS
Tools and Special Tools
General Mechanics Tool Kit (WP 0541 00, Item 57)
Multimeter (WP 0541 00, Item 29)
Slip Joint Pliers (WP 0541 00, Item 33)
See your -10
Engine stopped (see your -10)
Carrier blocked (see your -10)
Heater HI-LO switch in LO
M548A1 and M548A3 troubleshooting procedures are the same even though component
locations are different. When needed, locators are used to show the different component
The M548A3 has a fuel filter in between the fuel pump and the heater.
1. Press heater-on indicator cover lens.
2. Does indicator light come on?
GO TO BY (PAGE 0085 00-3)
1. Release heater-on indicator.
2. Move RUN-OFF-START switch to START.
3. Does heater blower come on?
GO TO CY (PAGE 0085 00-5)
1. Check if heater fuel pump comes on.
2. Does heater fuel pump come on?
GO TO EY (PAGE 0085 00-7)
1. Check on how many minutes it takes heater-on indicator to come
2. Does heater-on indicator come on in less than three minutes?
GO TO GY (PAGE 0085 00-8)