TM-9-2540-207-14-P

HEATER, VEHICULAR COMPARTMENT, MODEL: A20

TECHNICAL MANUAL; OPERATOR, FIELD, AND SUSTAINMENT MAINTENANCE MANUAL INCLUDING REPAIR PARTS AND SPECIAL TOOLS LIST

JULY 2007

TM-9-2540-207-14-P - Page 174 of 288

TM 9-2540-207-14&P

6-10

4

CHECK WIRE HARNESS FOR

CONTINUITY AND SHORTS

CHECK 2 WIRES FROM THE VENT FAN BOARD TO THE

LOGIC BOARD FOR CONTINUITY:

P11-PIN12 TO P1-PIN3

P11-PIN4 TO P1-PIN12

CHECK

FOR MV SIGNAL

BETWEEN

P11-PIN13 AND P11-PIN5 FOR BT SENSOR

P11-PIN14 AND P11-PI N 6 FOR XT SENSOR

CHECK FOR A MINIMUM OF 150K RESISTANCE OR

OPEN LINE

BETWEEN

P11-PIN13 TO CHASIS GROUND AND

P11-PIN14 TO CHASIS GROUND

IF ANY CHECK FAILS

REPLACE WIRE HARNESS

RESTART HEATER

COMPLETE THE FOLLOWING CHECKS AT ROOM

TEMPERATURE AND WITH THE SENSOR HEATED TO

GREATER THAN 600C.

CHECK FOR MV SIGNAL BETWEEN

P11-PIN13 AND P11-PIN5 FOR BT SENSOR

P11-PIN14 AND P11-PIN6 FOR XT SENSOR

CHECK FOR GREATER THAN 10K

RESISTANCE BETWEEN;

P11-PIN13 TO CHASIS GROUND AND

P11-PIN14 TO CHASIS GROUND

IF ANY CHECK FAILS REPLACE WIRE HARNESS

RESTART HEATER

4

CHECK VENT FAN BOARD FOR LOOSE

SOLDER JOINTS

REPLACE VENT FAN BOARD

RESTART HEATER

5

CHECK LOGIC BOARD FOR LOOSE

SOLDER JOINTS

REPLACE LOGIC BOARD

RESTART HEATER

NOTE:

THIS FAULT MAY OCCUR ONLY WHEN THE SENSOR IS HEATED TO OPERATING TEMPERATURES.

AFTER COOLING THE FAULT CAN CLEAR ALLOWING THE UNIT TO BE STARTED, OPERATING BREIFLY

UNTIL THE SENSOR IS HEATED.