8-TROUBLESHOOTING
Heating,ventilation,airconditioning(HVAC)-Troubleshooting
Problem
PossibleCauseCorrection
Dustentersthecab
ImpropersealaroundlterelementChecksealcondition
BlockedlterCleanorreplacelter
DefectivelterReplacelter
Excessiveairleak(s)arounddoorsand
windows
Repairandsealairleak(s)
BlowermotorairowlowBlockedlterorrecirculationlterCleanorreplacelter(s)
Heaterradiatorcoreblocked
Cleanradiatorcorethoroughly
BlowermotornotworkingFuseblown
Replacefuse
Cabindoesnotheatup
Enginenotreachingoperatingtempera-
ture.Thermostatstuckopen
Replacethermostat
Heaterhosefromenginetocabradiator,
kinkedorblocked
Ensurewaterowtoheaterradiatorisad-
equateandnotrestricted
Cabindoesnotcool
Heatercontrolturnedon
Turnthetemperaturecontrolknobfully
counterclockwiseformaximumcooling
HeatercontrolvalvestuckinopenpositionFreeupvalveorchangeasrequired
TemperaturenotstableLowenginecoolantT opupcoolantrecoverytank
8-17