marksmen1
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It's a bit difficult to describe, so I will try my best.
When I first got my HMMWV, the wait light would stay on about 10 seconds when the switch was in the "run" position. I also noticed that the volt meter would swing from low yellow to high yellow until the vehicle was started. The engine would start up instantly once the switch was turned to the "start" position. If any other devices were switched on (windshield wiper, heater) while in the run position, they would work.
A few weeks ago, I noticed that the wait light would not go out in the "run" position, even after waiting for long periods of time, and the volt meter would not cycle between low yellow and high yellow as it had previously done. I also noticed that the heater would no longer turn on while the wait light was one; however, the wipers still worked. If i hold the switch in the "start" position, the engine would start after turning over a couple of times. The wait light would stay on until the engine reached 200-220 degrees, and then it would go out on its own. Once the wait light went off, the heater would work again. Once the engine warmed up and I shut it off and switched back to the "run position", the wait light would come for a split second before going out. The vehicle would start up immediately on a warm engine as well. I figured this was due to bad glow plugs.
Today, I installed new Wellman glow plugs. I still had the issue of the wait light not going out even after waiting extended periods of time and the the volt meter would not swing between low yellow and high yellow; however, when switched to the "start" position, the vehicle would start up almost immediately. The heater would still not come on until the "wait" light went out. As before, once the engine warmed up, the wait light would go out immediately in the "run" position. The heater would also work once the wait light was out.
After allowing the engine to cool down, I unplugged the connector for the heater/blower and tried starting the vehicle again. This time, I noticed that the volt meter would immediately drop to the low yellow position and hold there instead of bouncing low and high as it did with the original glow plugs installed. After a few seconds, the wait light went out and the vehicle started up immediately.
Any insight as to what the issue might be? It seems there is something related to the heater being connected while the engine is cold that is preventing the glow plugs from cycling properly.
It is a 1993 M998 with the 6.5l engine.
When I first got my HMMWV, the wait light would stay on about 10 seconds when the switch was in the "run" position. I also noticed that the volt meter would swing from low yellow to high yellow until the vehicle was started. The engine would start up instantly once the switch was turned to the "start" position. If any other devices were switched on (windshield wiper, heater) while in the run position, they would work.
A few weeks ago, I noticed that the wait light would not go out in the "run" position, even after waiting for long periods of time, and the volt meter would not cycle between low yellow and high yellow as it had previously done. I also noticed that the heater would no longer turn on while the wait light was one; however, the wipers still worked. If i hold the switch in the "start" position, the engine would start after turning over a couple of times. The wait light would stay on until the engine reached 200-220 degrees, and then it would go out on its own. Once the wait light went off, the heater would work again. Once the engine warmed up and I shut it off and switched back to the "run position", the wait light would come for a split second before going out. The vehicle would start up immediately on a warm engine as well. I figured this was due to bad glow plugs.
Today, I installed new Wellman glow plugs. I still had the issue of the wait light not going out even after waiting extended periods of time and the the volt meter would not swing between low yellow and high yellow; however, when switched to the "start" position, the vehicle would start up almost immediately. The heater would still not come on until the "wait" light went out. As before, once the engine warmed up, the wait light would go out immediately in the "run" position. The heater would also work once the wait light was out.
After allowing the engine to cool down, I unplugged the connector for the heater/blower and tried starting the vehicle again. This time, I noticed that the volt meter would immediately drop to the low yellow position and hold there instead of bouncing low and high as it did with the original glow plugs installed. After a few seconds, the wait light went out and the vehicle started up immediately.
Any insight as to what the issue might be? It seems there is something related to the heater being connected while the engine is cold that is preventing the glow plugs from cycling properly.
It is a 1993 M998 with the 6.5l engine.