EESS PCB replacement for the HMMWV ?

[Dock Rocker]

Have you checked your grounds?

 

[samuraicrawler]

I am planning on making some time for that tomorrow. I checked the ground next to the transmission bell housing on the driver side but could't find an others, Ive read that there are 5 and they are problematic. Once thing strange is my truck is in very excellent condition and has many new parts and my EESS box looks very new and even has new bolts, I could see it going bad after 20 plus years but wouldn't expect a newer one to go bad.

 

[DatGuyC]

After you charged the batteries back up and connected to them to the truck while everything was off, was there a spark? There isn't supposed to be any load without anything on. I've had my s3 box fry a relay which left the glow plugs on and killed the batteries really quick.

 

[samuraicrawler]

After you charged the batteries back up and connected to them to the truck while everything was off, was there a spark? There isn't supposed to be any load without anything on. I've had my s3 box fry a relay which left the glow plugs on and killed the batteries really quick.

I don't think there was any spark but I don't remember 100%. If there was then the start switch would be bad because I believe that cuts off all power. I can check tomorrow but I'm pretty sure there wasn't any spark.

 

[gcbennet]

I had the same issue recently. The wait light stopped coming on and then the next day my batteries were dead. I recharged the batteries and upon reinstallation i could hear the audible clunk of the box when i hooked up the neg terminal. The box was draining the power even with the run/start switch in the off position. This is my second new box in less than a year, and at $500'ish USD each it's getting expensive. I replaced the batteries and plugs when the previous box shi*t the bed and the second new one worked great for a few months before this whole episode. The vendors i bought the boxes from won't replace electronic parts as a rule, so it looks like i'm stuck forking out more $$$ for a new replacement. Just an FYI both of the boxes are of different manufacture so i'm thinking neither is any better than the other.

 

[sesykes71]

Our 1987 M998 with Nartron S3 box has been starting and running fine. Two days ago, when we tried to start it, the wait light just blinks and no start. The batteries were going to be replaced anyway so we did that but the same problem. I have cleaned the contacts for the temperature sensor as well as the control box, checked the grounds. I want to try a new TPC but the part number for the box and the TPC are the same. I called Nartron but as of yet they haven't provided any information.
Short of replacing both units how should I proceed?


Steve

 

[gcbennet]

No start as in you turn the run/start switch and nothing happens? Or merely turns over on cold cylinders without starting before the battery dies?

 

[sesykes71]

No, it cranks, albeit not every time, sometimes it just does a half turn then on the retry it turns over normally, but no start. I hear a relay click in the S3 box, the wait light flashes every few seconds.
It has brand new batteries which measure correctly, new connectors, all cleaned. I have checked the grounds. I have checked that the fuel relay works.
I have contacted Nartron for troubleshooting info, hopefully they will provide something. I have a troubleshooting guide from AMG but it doesn't give any information on new control boxes, only the old prestolite units. The Army says they would update the TM, but I haven't found one.
The odd thing is that it has been starting and running fine, this came up suddenly.

No start as in you turn the run/start switch and nothing happens? Or merely turns over on cold cylinders without starting before the battery dies?

 

[Wile E. Coyote]

Box might be full of water, but if you have a DVM handy that does resistance, pull a couple of the glow plug wires off and measure between the tip of the glow plug and a clean ground with the meter set to a low ohms scale or diode check. If the meter indicates an open circuit, the plug is bad - and chances are a bunch of others are too which you can check the same way. I've had boxes just sort of sit there clunking away trying to output to a zero load as the plugs were either all bad or mostly bad. Sometimes you can be running on 5 out of the 8 working and not notice a problem in average weather, but then one day you have 4 out of 8 (or worse) and that's that.

 

[sesykes71]

I found the problem. The Nartron control box is burnt up. A new KDS unit is on the way. What led me down a wrong path was thinking that when trying to start it acted like the starter was bad, perhaps a quarter turn and after a retry it would turn normally. I thought the control box only activated a solenoid which activates the starter solenoid. Lesson learned.

Steve

 

[Wile E. Coyote]

The earlier control boxes (Prestolite original types) had relays, which, if I remember correctly, were one for the Starter, one for the Alt-to-Bat connection, and one for the Glow Plug circuit. So, you'd get boxes that would clunk and not connect Alt --> Bat so no charging, and boxes that would clunk but not engage the starter, and boxes that would clunk and not run the glow plugs. Or didn't clunk at all. Or clunked with a sound like banging two baseball bats together under about 3 feet of water (which wasn't far wrong.)

Then they went to a few different designs in the KDS world, most notably the removal of the Glow Plug Relay and the substitution of a solid-state FET type solution which...well...had its own problems too if people ignored the part of the instructions where you were supposed to change out all your glow plugs for new ones, because the FET setup seems to rely on a known resistance as a load - which won't be the case if you have two bad plugs or something. KDS Yellow with the associated yellow banded sensor (screws in the coolant crossover) seems to work the best out of the ones I've tried for the movie fleet. KDS Green label (which doesn't need a sensor of any type) seems to have 100% failure rate (also a FET/ solid state design), perhaps for the same reason. I gave up trying to reverse-engineer what looks like a grossly overcomplicated circuit for what it's supposed to do.

A bunch of the other circuits which were switch/ relay controlled in the original Prestolite design (main power to the 3-lever light switch for one) are now simply bridged in the KDS design - in fact, I modded one of the KDS Yellow boxes and put in spare relay from another defunct KDS Yellow box and wired it up to run as a Glow Plug relay, then drilled the box for a pushbutton switch facing the driver's legs to manually run the glow plug circuit (12 secs on the button.) That's my failsafe running spare in case something goes haywire on a movie set or at some MVPA event and I don't have a spare box of whatever type/ generation fitted to that particular HMMWV, because a box so modded will work on every generation of the beasts, and it too doesn't need the GPC/ Temp Sensor screwed into the water jacket for anything and just ignores it.

 

[AndyC]

I did a Resistance check per tech trouble shooting manual on 3 different Nartron GPCs and they all failed the resistance checks. Do you know if there are different checks for different GPCs?

 

[Retiredwarhorses]

The earlier control boxes (Prestolite original types) had relays, which, if I remember correctly, were one for the Starter, one for the Alt-to-Bat connection, and one for the Glow Plug circuit. So, you'd get boxes that would clunk and not connect Alt --> Bat so no charging, and boxes that would clunk but not engage the starter, and boxes that would clunk and not run the glow plugs. Or didn't clunk at all. Or clunked with a sound like banging two baseball bats together under about 3 feet of water (which wasn't far wrong.)

Then they went to a few different designs in the KDS world, most notably the removal of the Glow Plug Relay and the substitution of a solid-state FET type solution which...well...had its own problems too if people ignored the part of the instructions where you were supposed to change out all your glow plugs for new ones, because the FET setup seems to rely on a known resistance as a load - which won't be the case if you have two bad plugs or something. KDS Yellow with the associated yellow banded sensor (screws in the coolant crossover) seems to work the best out of the ones I've tried for the movie fleet. KDS Green label (which doesn't need a sensor of any type) seems to have 100% failure rate (also a FET/ solid state design), perhaps for the same reason. I gave up trying to reverse-engineer what looks like a grossly overcomplicated circuit for what it's supposed to do.

A bunch of the other circuits which were switch/ relay controlled in the original Prestolite design (main power to the 3-lever light switch for one) are now simply bridged in the KDS design - in fact, I modded one of the KDS Yellow boxes and put in spare relay from another defunct KDS Yellow box and wired it up to run as a Glow Plug relay, then drilled the box for a pushbutton switch facing the driver's legs to manually run the glow plug circuit (12 secs on the button.) That's my failsafe running spare in case something goes haywire on a movie set or at some MVPA event and I don't have a spare box of whatever type/ generation fitted to that particular HMMWV, because a box so modded will work on every generation of the beasts, and it too doesn't need the GPC/ Temp Sensor screwed into the water jacket for anything and just ignores it.

why the Guvment didn't install a manual switch on the box is beyond me...only makes sense.
i have opened the new Nartron and KDS S3 boxes, I have found the Nartron still retains its relays and the KDS unit is for the most part all IC. I may have the 2 MFG's backwards, but they are most definetly different engineering thoughts.

 

[sesykes71]

M998 Starting problems continue

About the 10th of March I replaced the Nartron Smart Smart box with a brand new KDS unit and sensor. Now less than 30 days later, it wouldn't start again. We thought we smelled the distinctive odor of electricity gone bad. Opening the new KDS box we found burnt traces on the circuit board. Of course no warranty. I have ordered a new box but before installing it I want to try to insure that it won't happen again, at least for awhile. I did find 4 glow plugs open and have ordered 8 new plugs to install at the same time. When the new box was installed the last time, every once in awhile the starter wouldn't turn or would turn very slowly but upon retry it would turn fine and start the motor. We thought it had a dead spot or something. Now with the box burnt up, I am not so sure. I rigged a way to try the starter with the box out and it seems to turn as it should. I have checked the wiring and can't find anything wrong but there must be. Any ideas? Wile E. Coyote said he made a manual glow plug control using a damaged box. Can the HMMWV be run that way? There are a bunch of circuits that go into the control box, how are they dealt with? I would sure just like to press a button for a few seconds than keep replacing these control units. Steve

 

[sesykes71]

Again another EESS burnt up. Same failure as last time. I opened the two week old control box to find the burnt traces. It goes from Pin E of the box to a relay then from the relay to Pin I. Pin E is battery voltage via the starter. Pin I goes to the solenoid. I have found that the relay closest to the damaged trace is welded closed. The relay is a $2.97 part made in China.

I am glad that the protective box protects the vehicle by burning itself up.

Without the S3 box connected and jumping the solenoid made the starter crank but wouldn't stop cranking. I got a pretty good spark while yanking the neg cable off the battery. I have ordered a new starter which probably has been the problem all along. Also a new S3 box.

This is what the burnt box looks like.

 

[diesel dave]

Just curious. What was the problem?

 

[JAGWAH]

I'm curious as well.

I do see on Eriks Military Surplus site there are these notices:

Disconnect batteries before installing the control box. Failure to disconnect batteries before installing or removing control box connectors will damage the control box.

It is highly recommended to check the glow plugs before installing a new control box. Defective glow plugs may damage the control box.

The glow plug system will draw approximately 100 amps. The vehicle batteries must be in good condition for the preheat and start system to function. If the batteries cannot crank the engine they won’t operate the glow plugs.

Only the 60 amp alternators can power directly through the control box. Basic and A1 vehicles upgraded to 100, 200, and 400 amp alternators must have the alternator wiring harness modification in place (done when the alternator is installed) so the alternators output does not go through the control box. Vehicles factory equipped with 100, 200, and 400 amp alternators have the battery direct wiring factory installed.

Don't know if any of these warnings would apply to this older thread, but maybe useful for those encountering similar issues...

Chris.

 

[sesykes71]

The actual problem turned out to be a bad starter. We replaced all the glow plugs, re-did all the grounds and connections. It worked for awhile but was very hard starting, the cranking was too slow.Finally it burnt up another EESS box. I managed to convince my boss to replace the starter and repaired the EESS box. After the starter replacement, it starts correctly. It has worked for several months with the new starter and repaired box so we replaced the repaired box with a new one and everything is good now.


Steve

 

[Wile E. Coyote]

I've had lots of bad starters on diesels that draw far too much - many 6.2s and 6.5s in both CUCV and HMMWV - but also Ford 7.3s in our ambulances, which all seem to expire within about 10,000 miles of one-another.)

 

[Wile E. Coyote]

Ensuring you have good batteries is important because as the available voltage decreases, whatever's being driven by the batteries starts to draw more current. With the old, original PCB boxes (silver label Prestolites etc.), the extra current drawn across copper relay contacts wouldn't matter - within reason - but the newer designs have that current passed through solid-state devices attached to heatsinks, and those devices have x-tolerance for going outside their rated current, at which point they turn into expensive fuses.

That said, you'd expect all the KDS Yellow and Green label boxes (and SSI equivalents) of the solid-state design to have failures of those components, but...the ones I've briefly played by way of post-mortem seem to have the actual heavy current-carrying FETs working - but not the associated current sensing/ turn-on// turn-off control systems. Perhaps some associated transistor (or resistor) or IC path goes open when the current from low batteries goes outside tolerance levels - but if that's the case - I couldn't find it/them. But I also didn't spend a lot of time on it, because without a schematic or even a block diagram it was impossible to narrow down.

I think the warning concerning the alternators is because the output of the alternator still runs through the S3/ EESS boxes for the sake of interchangeability/ backwards compatibility, even though it's just a direct-wire shunt inside the box. The problem, I guess, is that the gauge of the wiring isn't good enough to carry any more than the top output of the 60A alternator - so when you get into the theoretical max output of the other alternators - you're outside the current spec for the wire gauge used.