How To Repair HMMWV EESS S3

[Jon0249]

Sadly, these symptoms ring true with me. I have the Nartron EESS box. Last spring (in Texas, warm), I decided I would change my glow plugs as a matter of preventive maintenance. One was bad, but the rest had not been compromised. New ones seemed to work ok, but it was already 75+ weather, so looking back, I wouldn't have known whether they were bad or not. However, I do remember losing the after-glow effect on my voltage gage. Dumb and happy could best describe my frame of mind at that point. I was a bit concerned that I wasn't always in the green zone, charging as it should, so I fabbed a ground cable. That worked, sort of. Still couldn't explain why it wasn't charging like a racehorse... And where did that pesky after-glow run off to?

Warhorse, your admonitions were prescient. I didn't pay close enough attention to disconnecting the batteries, and must have fried the box. That would explain the absence of the after-glow. What I didn't know at the time was that the GPs were constantly on. First snap of cold weather and it wouldn't start. Still exercising my right to be stupid, I replaced the GPs last week. It started right up. Once. And now all the factors point to what I should have seen last fall.

Not too jazzed about ponying up the dough for a new box, but other than sitting idle until warmer weather, that seems to be my only option. I'll pry open the box to see if anything is evident, because I've still got current to the GPs that is affecting my charging.

I'm sure the engineers had good intentions, right?

 

[Retiredwarhorses]

Sadly, these symptoms ring true with me. I have the Nartron EESS box. Last spring (in Texas, warm), I decided I would change my glow plugs as a matter of preventive maintenance. One was bad, but the rest had not been compromised. New ones seemed to work ok, but it was already 75+ weather, so looking back, I wouldn't have known whether they were bad or not. However, I do remember losing the after-glow effect on my voltage gage. Dumb and happy could best describe my frame of mind at that point. I was a bit concerned that I wasn't always in the green zone, charging as it should, so I fabbed a ground cable. That worked, sort of. Still couldn't explain why it wasn't charging like a racehorse... And where did that pesky after-glow run off to?

Warhorse, your admonitions were prescient. I didn't pay close enough attention to disconnecting the batteries, and must have fried the box. That would explain the absence of the after-glow. What I didn't know at the time was that the GPs were constantly on. First snap of cold weather and it wouldn't start. Still exercising my right to be stupid, I replaced the GPs last week. It started right up. Once. And now all the factors point to what I should have seen last fall.

Not too jazzed about ponying up the dough for a new box, but other than sitting idle until warmer weather, that seems to be my only option. I'll pry open the box to see if anything is evident, because I've still got current to the GPs that is affecting my charging.

I'm sure the engineers had good intentions, right?

replace the Nartron with KDS S3 and new plugs...end of problem

 

[drivebymashing]

I just bought a 85 humvee. alternator isnt charging I drove it about 10 miles ran great. The Smart start box got really hot and my humvee would not shut off. So I snuffed it out with a piece of plastic over the intake. I disconnected smart start box wiring hoping it would cool down and be fine. I did NOT disconnect the batteries. I didnt know i needed too... Now with everything cooled down everything works except it wont turn over... did my dead alternator kill my smart box or did i kill it by not dissconecting batteried first? Either way why is this little box keeping my humvee from running... grrr

 

[Farnorth]

With a box that the glow circuit has failed or is acting up, the following parts will get you going. Ford external starter solenoid in 24V version from Napa, push button activator switch and some wire and connectors. Install this system in place of the glow plug circuit and just leave that failed box in place. I've done this to two of my humvees and love it. No more wondering if your box is frying your glow plugs or if its going to run your glow plugs at all. I push and hold for 8 seconds each start and it fires right up every time. The rest of the system in these boxes seem fairly reliable so why not just get that glow plug circuit out of there all together. Even if it was working I think I would still run an external glow circuit.

 

[drivebymashing]

Does the smart box control the starter? My starter won't engage.

 

[Milcommoguy]

Yes it does. Has simple logic to lock-out starter (shifter neutral safety switch) and (engine running feed from alternator).

 

[drivebymashing]

So what can I do to fix it other than replace a 600 dollar box

 

[drivebymashing]

What else is on this engine other than glow plugs and a starter? I dont see why this smart box has killed my humvee... I miss my deuce no smart box on it.. Never failed to start...

Pictures aren't very clear. Very few pieces on it aren't melted to a crisp. Did my bad alternator cause this?

 

[tanhmmwv]

I think it has to be a grounding issue. possibly alternator? thought the same thing with mine, removed it and had it tested.
it was working properly.

here is what mine looked like back in March 2018. I had the KDS green label PCB. it appears to happen at random, on all boxes.
this is why I say grounding issue.
could smell burning while driving down the road, wait light and park brake illuminated.
I was lucky and glow plugs did not swell.

do you have the 3 lever or push button light switch?

 

[drivebymashing]

3 lever. I could also smell burning Mine wouldnt shut off after the burning smell started. I havent checked my glow plugs yet.

 

[DatGuyC]

I'd say moisture probably got into your box and shorted things out. Look how corroded the relay is.

 

[NormB]

replace the Nartron with KDS S3 and new plugs...end of problem

DOH!

I keep confusing the two.

What RWH said. THAT box.

Edit: wrong post. But there’s a whole lot of box/starter/glowplug posts.

 

[fallguy]

Hi folks,
I just registered here. I find your post interesting 'cause I have the same issue with my recently bought 1985 HMMWV. The glow control lamp blinks for a fracture of a second but the system does not glow. This happens sometimes and sometimes it works.
The told me, they had changed the PCB lately. So I try to find another reason than this magically box *grrr

 

[tanhmmwv]

FIRST, easiest "possible" fix if you have the push button light switch....
remove it and install the old 3 lever light switch.
the push button switch in an EPIC disaster in a HMMWV.

Which box do you have in the truck? can you attach a photo?
from under the dash is best.

if you do not have the push button switch....
I would start by disconnecting the batteries.
Then unplug the PCB from the body harness under the dash and from the engines harness under the hood near the washer bottle.
Then run through the multi meter tests in the troubleshooting TM.
making sure your wiring harnesses (body and engine)are good is where to start.
Then test the Alternator/generator, circuit breakers, relays, ect...
most of the time... it end's up being a grounding issue.
which is why you disconnect the batteries.
adding a new grounding harness to ground all major components (engine, PCB, body, starter and alternator) will usually fix allot of issues.

replacing the PCB will be VERY expensive if mis-diagnosed.
this should be done only if 100% sure the vehicle is grounded properly.

let us know what you find
good luck!

 

[Action]

Hi folks,
I just registered here. I find your post interesting 'cause I have the same issue with my recently bought 1985 HMMWV. The glow control lamp blinks for a fracture of a second but the system does not glow. This happens sometimes and sometimes it works.
The told me, they had changed the PCB lately. So I try to find another reason than this magically box *grrr

I would get an ohm reading from each plug.

 

[fallguy]

well, I spent lot of my sunday today in troubleshooting. Finally I quit at the 3rd. GP. Left front - I loosens it but it won't get out (mechanical problem). I re-attached all the cables and the glowing process worked again. I've been told from the seller, they replaced the PCB and the GPs. So I tend to install an old fashioned glow button to avoid further issues.. what do you think? Any idea how to do it?
later on I'll upload a pic of the PCB....

 

[fallguy]

so this is the PCB of my HMMWV

 

[tanhmmwv]

how many glow plugs will not come out? did you check all 8?
there is a steel soldiers thread about the manual Glow button, great idea!
plugs could have failed due to bad plugs or bad GP controller, or bad PCB.
or poor ground....

 

[tanhmmwv]

does the ametek use a glow plug controller in the water crossover?

 

[Action]

well, I spent lot of my sunday today in troubleshooting. Finally I quit at the 3rd. GP. Left front - I loosens it but it won't get out (mechanical problem). I re-attached all the cables and the glowing process worked again. I've been told from the seller, they replaced the PCB and the GPs. So I tend to install an old fashioned glow button to avoid further issues.. what do you think? Any idea how to do it?
later on I'll upload a pic of the PCB....

You can check the ohm reading with the plug installed.