TM-9-2320-387-24 HMMWV Direct Support & General Support Maintenance Manual Volume 1 Download
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TM 9-2320-387-24-I REFERENCE INFORMATION GLOW PLUGS CIRCUIT Dead glow plugs draw virtually no current, but other parts of the vehicle are drawing some current-up to 8 amps. If any glow plugs are drawing any current, then the PCB is probably OK. I For a good description of how glow plugs cycle and how to check for proper cycling, refer to page 2-293. --I @ WARNING Disconnect negative battery cable before disconnecting and reconnecting PCB harness. WARNING There is battery voltage at the PCB at all times. Failure to disconnect battery cable will nsult in damage to equipment or injury to Personnel. If most or all of the glow plugs are bad, you may also have a problem with the PCB or the glow plug controller which caused them to go bad (usually they bum out from being on too long or not turning off at all). After replacing the bad glow plugs, rerun the glow plugs test chain paying special attention to the glow plugs cycling, especially that they turn OFF when they should. 1 Replace glow plugs, wires, or harness (para. 3-39). 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 = 1.000 amps. To get current, multiply millivolts x 10. CHECKING GLOW PLUGS 8 THEIR WIRFS 1. Disconnect ALL the glow plugs. 2. Disconnect the neoative battery cable. Disconnect the PCB connector harnessfrom the PdB. Reconnect the negative battery cable. Measure me resistance between pin D in the engine connector harness of the PCB and ground. There should NOT be continuity (resistance reading off the scale). If there is continuity, repair or replace me harness. Repeat the following for each glow plug: 3. a. Reconnect the wiring harness to the glow plug while you repeat the resistance measurement described in step 2. When you reconnect the wire to the glow plug, the resistance should drop to between 1 and 2 ohms (glow plugs are typically 1.6 ohms). b. If step A passed: disconnect the glowptug again, making sure the resistance goes off scale again. Repeat step A for me next glow plug. C. If step A failed: then either the glow plug or its wire is no good. Take the wire off the glow plug again and measure the resistance from the glow plug to the engine block. If the resistance is 1 - 2 ohms, then the cable is no good. Otherwise replace the glow plug and check the cable for continuity, just to be sure. 4. Reconnect the PCB and all wires. 2-295