TM-9-2350-311-20-1

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

TECHNICAL MANUAL; UNIT MAINTENANCE MANUAL FOR HULL, POWERPLANT, DRIVE CONTROLS, TRACKS, SUSPENSION, AND ASSOCIATED COMPONENTS

AUGUST 1994

TM-9-2350-311-20-1 - Page 414 of 1275

TM 9-2350-311-20-1

3-3 TROUBLESHOOTING CHART — CONTINUED

ac. WINTERIZATION KIT CIRCUIT — CONTINUED

(1) COOLANT HEATER FAILS TO OPERATE

INITIAL SETUP

Tools

General mechanic’s tool kit (item 64, Appx H)

Engine access door open (TM 9-2350-311-1 O)

Multimeter (item 36, Appx H)

Transmission access doors open (TM 9-2350-311-1 O)

TA-1 probe kit (item 43, Appx H)

Battery access doors open (TM 9-2350-31 1-10)

A

1. Disconnect battery ground leads.

2. Disconnect bulkhead-to-coolant heater

control box wiring harness from coolant

heater.

3. Place red lead of multimeter on pin C (lead

430C) and black lead to ground.

4. Reconnect battery ground leads.

5. Turn MASTER switch ON and heater

control switch to start.

6. Check for voltage.

7. Turn MASTER and heater control switches

OFF.

Is voltage present?

1

Replace coolant heater assembly

CONTINUED ON NEXT PAGE

3-314

Equipment Conditions