COOLANT NOT WARMED WHEN COOLANT HEATER CONNECTED TO POWER SOURCE (Cont)

TM 9-2320-285-24-1

2-68.

HEATERS TROUBLESHOOTING (CONT)

MALFUNCTION

TEST OR INSPECTION

CORRECTIVE ACTION

COOLANT NOT WARMED WHEN COOLANT HEATER CONNECTED TO POWER SOURCE (Cont)

Step 2.

Connect power cord between junction box and 110 Vac outlet.

Check if heater pump is operating (a slight buzz should be heard, indicating heater pump is operating).

WARNING

Coolant heater operates from 110 Vac power source. Disconnect winterization system cable

from receptacle at front bumper of tractor before proceeding. Serious injury or death can

result from contact with energized 110 Vac power lines.

Disconnect power cord from 110 Vac outlet and junction box.

If heater pump buzzes, go to step 3 below.

If heater pump does not buzz, go to step 7 below.

Step 3.

Remove coolant heater thermostat cover (para 2-73e).

Use an ohmmeter to check continuity of 3-wire cord between thermostat and junction box (para 2-73f).

If continuity is not obtained, replace 3-wire cord (para 2-73e).

If continuity is obtained, go to step 4 below.

Step 4.

Disconnect 3-wire cord from coolant heater thermostat (para 2-73e).

Use an ohmmeter to check continuity of thermostat.

If continuity is not obtained, replace thermostat (para 2-73e).

If continuity is obtained, go to step 5 below.

Step 5.

Disconnect 3-wire cord from coolant heater unit (para 2-73e).

Check continuity of heater element.

If continuity is not obtained, replace coolant heater unit or

If continuity is obtained, go to step 6 below.

2-767