MMMWV Wait Light

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New member
Columbus Ohio
I recently purchased a 92 HMMWV and ran it all summer with no problems. Since it has gotten colder, like any diesel it has gotten harder to start in the cold. Currently, the wait light doesn't come on and it turns over but won't start at all. I had the batteries recharged... They were weak because the previous owner had a light bar wired directly to the battery which I assume was draining it over a period of time. Even after charging them, still no luck. I have read everything from bad glow plugs, bad control box, and need for grounding kit.

Any help or expertise would before I blindly start buying parts.
Even just a place to start would be helpful.

Thanks in advance fellas


Well-known member
San Jose, Ca
Download a copy of the -20 TM and go thru the start troubleshooting section. TMs are free on plenty of sites in the internet and here on the SS Forums. The Technical Manuals are written for a base level mechanic and will walk you through the known issues related to starting. They probably cover 99% of the problems your ever going to have with your truck.

Download here:
Last edited:


Active member
Steel Soldiers Supporter
Thanks sir,
Much appreciated. In your experience is it ever a grounding problem? Should I look at that too?
One of the first "hacks" any new HMMWV owner should do is the grounding harness and/or glow plug replacement.

Smart start box is probably #2 or 3 on the list.

Yeah, yeah, fluids, brake pads, coolant, etc, I'm just mentioning things to help it start reliably.

When I upgraded to a 200A alternator, I took the connections off the starter - all of them - the one area I hadn't really addressed earlier, and there was so much corrosion I was surprised the thing ever started at all.

Clean/lube/replace connectors as you go, too. Dash panel, etc.

I think it pays off, but yeah, grounding harness is a must.

have fun.
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