Chevrolet Light Duty Truck 1973 Service Manual page 111

LOW R EFR IG ER A N T CHARGE PROTECTION SYSTEM DIAGNOSIS
SUGGESTED CORRECTIONS FOR BLOWN THERMAL FUSE*
CAUSE
Low refrigerant charge or totally discharged system .
Inoperative expansion valve. (See Service Diagnosis
chart.)
U nderhood tem peratures exceeded 26 0°F.
Therm al fuse blow n during charging.
F aulty Superheat Switch.
G rounded Superheat Switch.
New Therm al Fuse Blows Im m ediately.
*Due to Superheat Sw itch Sensing A bnorm al System C ondition and Protecting System .
CHECK LIST SHOWING POSSIBLE CAUSES AND
HEATER A ND AIR C O N D IT IO N IN G
CORRECTION
Inspect for leaks, repair, evacuate, recharge system
and th en replace therm al fuse.
Replace expansion valve according to norm al
procedures, recharge system and then replace the
therm al fuse.
Install new therm al fuse.
Jum p connector plug " B" & " C " term inals during
charging and replace therm al fuse.
Replace superheat sw itch according to proced ure,
recharge system and replace therm al fuse.
Repair ground condition and replace therm al fuse.
Check for and correct as follows:
A. Pinched, broken or bare wires.
B. Boot off of connector at switch.
C. Connector on thermal limiter reversed.
D. Connector shorted to switch body.
E. Refrigerant pipes cutting through boot at switch.
F. Connector off center on switch pin.
1A-85
LIGHT DUTY TRUCK SERVICE MANUAL