TM-9-2320-280-20 HMMWV Technical Manual Unit Maintenance Volume 1 Download
Page 417 of 890
TM 9-2320-280-20-1 REFERENCE INFORMATION Change 1 2-318.7 GLOWPLUGS Dead glowplugs draw virtually no current, but other parts of the vehicle are drawing some current, up to 8 amps. If any glowplugs are drawing any current, then the distribution box and glowplug circuit is probably OK. For a good description of how glowplugs cycle and how to check for proper cycling, refer to page 2-307. Disconnect ALL the glowplugs. Disconnect the negative battery cable. Disconnect the distribution box connector harness from the distribution box. Reconnect the negative battery cable. Measure the resistance between pin D in the engine connector harness of the distribution box and ground. There should NOT be continuity (resistance reading off-the-scale). If there is continuity, repair or replace the harness. Repeat the following for each glowplug: 1. 2. 3. 4. Reconnect the wiring harness to the glowplug while you repeat the resistance measurement described in step 2. When you reconnect the wire to the glowplug, the resistance should drop to between 1 and 2 ohms (glowplugs are typically 1.6 ohms). If step a passed; disconnect the glowplug again, making sure the resistance goes off-scale again. Repeat step a for the next glowplug. If step a failed; then either the glowplug or its wire is no good. Take the wire off the glowplug again and measure the resistance from the glowplug to the engine block. If the resistance is 1 - 2 ohms, then the cable is no good, otherwise replace the glowplug and check the cable for continuity, just to be sure. a. b. c. If most or all of the glowplugs are bad, you may also have a problem with the distribution box or the glowplug controller which caused them to go bad (usually they burn out from being on too long or not turning off at all). After replacing the bad glowplugs, rerun the glowplugs test chain paying special attention to the glowplugs cycling, especially that they turn OFF when they should. BATTERY CURRENT STE/ICE-R TEST 80 1. Start Test 80, battery current. 2. Displayed reading is in amps. The reading will be greater then 30 amps, depending on how many accessories you have on. BATTERY CURRENT MULTIMETER 1. Set the voltmeter to a DC volts scale of about 1 volt. 2. Connect the BLACK lead to the battery side of the current shunt and the RED lead to the other end of the current shunt. 3. Current shunt voltage is proportional to battery current, 100 millivolts = 1000 amps. To get current, multiply millivolts x 10. CHECKING GLOWPLUGS & THEIR WIRES Replace glowplugs, wires, or harness, refer to (para. 3-38). Reconnect the distribution box and all wires. Disconnect negative battery cable before disconnecting and reconnecting distribution box harness. There is battery voltage at the distribution box at all times. Failure to disconnect battery cable will result in damage to equipment or injury to personnel. WARNING