"Wait" Light not illuminating

My M998 with a 6.2 was sitting with the light switch in the "Stop Light" position for a while and the next time I went to fire it up the "Wait" light didn't illuminate. It wasn't left on run because the brake light wasn't on, so I wouldn't think the glow plug controller was affected. I thought maybe the battery was depleted, but it did eventually start up when I tried to turn it over. First time I've ever seen it smoke when it finally fired and it did take longer than normal to fire up. Is it possible I discharged the batteries too far and the batteries weren't able to heat up the glow plugs? It would seem very unlikely considering they were able to turn the motor over. Any suggestions?

Yes. Did you check the batteries

I didn't put a meter on them thinking they were fine since started. I've been looking for an excuse to buy a relocation kit and install an auxillary battery for an inverter and on board air. Now I have to convince my wife.

Relocation Kit ? Why not just upgrade to either the 100amp or 200 amp dual voltage alternator

Every 200 amp dual voltage alternator I've seen out there is over $1,000. An add a battery kit with acr and switch is $120 and a couple cheap batteries is $200. When I'm camping it gives me some reserve as well. Are there cheaper alternator options out there than what I've seen?

You said it sat for a while, then wait light didnt come on with next start. What was "a while"?

No more than 24 hours.

Wait light could be burnt out or PCB could be toast, but it sounds like I didn't start up as normal so I'd say PCB is shot.

PCB? Is that the glow plug control box?

Protective
Control
Box

check the glow plugs. it is free. if they are bad, maybe the pcb fried them.

And if the PCB is frying them, it's around $500-600 for a new box. Make sure you get actual 24 volt glow plugs and disconnect the batteries before replacing the PCB........ Glow plugs should have a resistance of 1.5-5 ohms when you check them.

Many points of failure surrounding the not so smart start box system. For the worked yesterday and now won't start problems take a look at the TM's (any problem for that matter) Read over the operation of system, breaking it down into simple / logical components. Coupled with the flow chart step by step guide and the gremlins will come forward.

Read through it a couple of times "on a dry run" on the couch with your favorite beverage near by. Pay close attention to the pictures as they count for a thousand words. Since you bought the books ?? make penciled notes, high lights, or doodles that you payed attention.

Being familiar with the TM' and understanding the components affected, will put you ahead of the pack, unless this is your day job.

Follow safety, before action and after action warnings. (like when to disconnect battery, etc.)

ALL Hmmwv problems have shown up on S.S. Some, but not most can be resolved with a simple question and a... that's it FIX here. More detailed systems is just a crap shoot (sometimes fun to guess) based on information presented.

Either way, learning the in and out and having the books is going to pay for its self many times over. Plus it adds value when sold. (that's what I told the boss lady)

I am not saying don't ask... Just think it thru and watch out for voodoo fixes and magic potions if your new to HMMWV gremlins.

NOT just a truck to drive, BUT a learning experiment %&#@ experience. (darn spell checker)


Who you going to call when broken down?

GHOST BUSTERS ?

CAM

I had already printed out all the manuals for reference and took a look today. You are right! The flow charts make it pretty easy to diagnose problems. Thanks for the tip. Now, I get to learn myself on how to do some of this stuff.

GREAT ! Remember TM's are written at less that high school level. All the design and engineering as been done over 40 years (generally). All (most all) we want to do is straighten out some of the dents, blow on some paint, work out some rattles or leaks, make it safe and go... and on the cheap as in hobby cheap. (That's a big $$ variable) Tons of other reasons to ownership. What's Yours ?? to the group.

Simple truck, drawings and text. Most repairs simple with simple tools. Patience and a box of band aids are money in the bank as to "take it to the dealer"

If there was a dealer nearby (no offence to RWH) I would be in the poor house (dog house too!) forever. So the hobby keep me under the hood or out on the trail. For the FUN FACTOR as in owner, operator, chief mechanic and driver.

Electrical problems in the Hmmwv can trip up the best. Be careful and logical. Visual inspection coupled with the mechanical connections, pay close attention to details. One of the most common failure points is the grounding thing.

I have researched this and the ground is a floating ground and is not directly referenced to frame ground as in old school system. IMPORTANT Note: NO engine ground strap to frame, NO body to frame straps, NO battery negative to frame. This is due to they wanted to incorporate electrical diagnostics (STE-ICE) into the the Hmmwv.

The actual ground is the grounding stud on the starter. From there individual ground leads find their way to key components, engine block, alternator, and body. Battery negative, shunt and big negative wire connecting to starter are slightly above system ground. If and a BIG IF... all connections are clean and tight it works.

Any of the above grounds become corroded , loose or broken then a serious ground loop is in effect and voltage and currents are going in directions you don't want. Put the Smart Box in the middle of it (it is) and now stray currents make it thru the 600 dollar fuse. Lights flicker, don't work right, truck won't start, CPU logic gets hung-up and glow plugs lock on and you don't know it till its to late. Add another 100 dollars and time.

DAMM... disconnected battery, replaced blown glow plugs, hooked back up (couldn't wait) and now it works. Your lucky Day... Till?

So that's why the recommended ground kit works. CHEAP insurance. DIY

When I did mine I didn't have the "Sticky" GROUNDING NOTE.

I did this after the first and last "Not So Smart Box" BBQ. I don"t need and have STE-ICE tester. Dumped the shunt. ADD, BIG fat ground strap from starter to frame, BIG short ground strap frame to body, one front and one rear, smaller ground 8ga from battery negative to battery box / cabin, done and DONE!

Many ways to nip it in the bud.

CAM

There is "glue" between all the body panels. Current may not flow well through it. The chassis is made up of painted parts bolted together, not welded like most other framed vehicles.

I have left the light switch in the blinker and brake mode for weeks and never had a problem. Sounds like you have a problem with the glow plug system. I would start with fully charging each of the batteries. It could have gone out and you not noticed untill the weather cooled off.

I was starting to think the same. It has 2 fairly new Optima Red Tops. When I did a search for a PCB I found this link and it seems to confirm what you guys have been saying.
https://www.steelsoldiers.com/showthread.php?83386-HMMWV-Glow-Plug-Gospel
I am really thankful for the help. This forum and everyone in it have been great.

Good link ^^.

When my eess went it fried all the glow plugs and that caused a no light situation.

I have even more questions now then I did when this post started. I guess that's part of the process of learning the ins and outs. I always thought the plug on the driver's side tunnel next to the parking brake and gear selector was a comm port. Is it that or where the STE/ICE is plugged in for diagnostics? Can you get power for accessories off of that plug? Are STE/ICE devices available at surplus auctions or are they still in use or in a government warehouse somewhere in case they are needed? Are there aftermarket options out there? I know it's asking a lot, but after more research, I have more questions. Also, is there anybody out there in Central Virginia?