peggrw
Member
- 26
- 58
- 13
- Location
- West Virginia
Have an unusual “NARTRON CONTROL REMOTE SWITCH” (control box) issue on a 1993 M1097 HMMWV. The control box will not engage the starter motor unless the internals of the control box are above 70 degrees Fahrenheit or so. This is independent of the ambient temperature or engine temp. Everything else seems to work just fine. I can easily solve this problem by replacing the control box ($900+), or even bypass the control box to energize the starter motor but would prefer not to spend money I could use for other priorities, or in bypassing the “motor running” check for the starter.
Have only had the HMMWV for a couple months. It worked great in September but as the ambient temperature dropped this Fall I found that the starter would only engage on warm days. Tracked it down to the control box. The box always goes through the normal glow plug routine perfectly, does a few brief afterglow cycles and works with the TSU to completely disable the glow plugs once the engine reaches temperature. All seems normal and that process is not affected by the outside temp. But the control box itself will not send voltage to the starter motor unless the box internals are above 70F. I have the bottom of the control box off and can precisely direct heat toward the solenoids and wiring with a heat gun set on low. Just enough to get the parts about 80F or so. Once up to temp the starter kicks over great.
The control box schematics are not available anywhere, and other than the exposed solenoids, the circuit board is encased in black epoxy and cannot be reverse engineered. I will loosen and tighten all of the solenoid and ground plane nuts just in case thermal expansion is causing a bad connection but I can’t think of what else to do. Can’t imagine it is a sticky solenoid since tapping each with a light hammer does not help. Easily started the HMMWV after warming the box this morning with an outside temperature of 19F.
Have only had the HMMWV for a couple months. It worked great in September but as the ambient temperature dropped this Fall I found that the starter would only engage on warm days. Tracked it down to the control box. The box always goes through the normal glow plug routine perfectly, does a few brief afterglow cycles and works with the TSU to completely disable the glow plugs once the engine reaches temperature. All seems normal and that process is not affected by the outside temp. But the control box itself will not send voltage to the starter motor unless the box internals are above 70F. I have the bottom of the control box off and can precisely direct heat toward the solenoids and wiring with a heat gun set on low. Just enough to get the parts about 80F or so. Once up to temp the starter kicks over great.
The control box schematics are not available anywhere, and other than the exposed solenoids, the circuit board is encased in black epoxy and cannot be reverse engineered. I will loosen and tighten all of the solenoid and ground plane nuts just in case thermal expansion is causing a bad connection but I can’t think of what else to do. Can’t imagine it is a sticky solenoid since tapping each with a light hammer does not help. Easily started the HMMWV after warming the box this morning with an outside temperature of 19F.
