TM-9-2350-311-20-2

HOWITZER, MEDIUM, SELF-PROPELLED, 155MM; M109A2, M109A3, M109A4 AND M109A5

TECHNICAL MANUAL; UNIT MAINTENANCE MANUAL FOR CAB, ARMAMENT, SIGHTING AND FIRE CONTROL, ELEVATING AND TRAVERSING SYSTEMS AND ASSOCIATED COMPONENTS

DECEMBER 1993

TM-9-2350-311-20-2 - Page 247 of 828

TM 9–2350–311–20–2

3–135

j.

NBC SYSTEM CIRCUIT — CONTINUED

(6)

NBC CONTROL BOX ASSEMBLY INDICATOR

LIGHT ILLUMINATES, BUT SECTION CHIEF’S

M3 ELECTRICAL AIR

HEATER DOES NOT

OPERATE.

INITIAL SETUP

Applicable Configuration

M109A4/M109A5 howitzers

Test Equipment

Multimeter (item 6, Appx H)

Tools

Artillery and turret mechanic’s tool kit

(SC 5180–95–CL–A12)

Equipment Condition

Vehicle MASTER switch to OFF (TM 9–2350–311–10)

CAB NBC POWER switch to OFF (TM 9–2350–311–10)

Is continuity present?

1.

Disconnect wire 136D from section chief’s M3

electrical air heater.

2.

Turn MASTER and CAB NBC POWER

switches to ON.

3.

Place red multimeter lead in wire 136D and

black lead to ground.

4.

Check for voltage.

Is battery voltage present?

A

yes

no

B

CONTINUED ON NEXT PAGE

WIRE 136D

–

+

Replace M3 electrical air

heater (para 15–2).

NBC POWER LEAD

ASSEMBLY CONNECTOR

PIN F

SECTION

CHIEF’S

HEATER

WIRE 136D

–

+

1.

Turn MASTER and CAB NBC POWER

switches to OFF.

2.

Disconnect NBC power lead assembly at J2

connector on NBC control box assembly.

3.

Place red multimeter lead connector of wire

136D and black lead to pin F of NBC power

lead assembly connector.

4.

Check for continuity.