Electrical issues.... Voltage gauge in yellow and not green

[Dirtbag]

So had my humvee for a few years now. Nothing ever gone wrong with it. Except for the smart box burning out the glow plugs recently. Bought an eess s3 box, and noticed that my old temp sensor was perma fried. So that prolly explained that.
Anyways, I haven't been able to drive the truck for a month or so now because of a back surgery. Anyways I get out to the truck yesterday and the wait light doesn't turn on. Starts up normally, but the charging guage is stuck in yellow. I tried tapping the guage lol. Anyways I have to herd some cattle so I'm going through pastures and the horn starts acting up. Then funky thing is when I press the horn the wait light illuminates...

Anyone have any ideas?

 

[Dock Rocker]

Clean your grounds and/or put on a grounding harness.


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[drivebymashing]

My horn used to work wait to start light quit . Glow plugs are dead. I have a new grounding harness... ugh I feel your pain.

 

[papakb]

My guess would be that your batteries are too low for the S3 box to operate. Make sure all your electrical connections are clean and tight and the batteries have a full charge and give it another try. If the truck starts and the voltmeter stays in the yellow your going to replace either the regulator in the alternator or the whole darn thing depending on which one you have. 60 amp regulators are readily available for about $60, anything else is going to cost you.

 

[98G]

In the yellow frequently means charged batteries but charging system INOP.

 

[Dirtbag]

Thanks guys.
That's what I figured what was going on. I have the 200 amp alternator. So she's going to have to wait a while till funds come in for a new generator and regulator.

 

[Action]

It will stay in the yellow for like 30 seconds after starting. Are you waiting longer than that?

 

[spoonsc1]

quick check: look up which two pins on the STE/ICE cannon plug and hook up a multimeter to see real voltage values instead of colors on a guage, should determine any indication problems versus bigger problems. (need more voltage than the batteries put out to charge them.)

 

[Dirtbag]

It will stay in the yellow for like 30 seconds after starting. Are you waiting longer than that?

That's the thing. I'm used to the glow plugs cycling on off after start up. And it didn't do that this time.
It has to be the eess connected since I'm not getting any wait light at all.

I'll go up tomorrow and see if I can get the glow plugs checked and swapped out.

 

[drivebymashing]

Same here mine doesn't dip in yellow at all. No wait to start light. I'm thinking mine is also eess. Not trying to hijack your thread just trying to help.

 

[Thecaptain]

Clean your grounds and/or put on a grounding harness.


Sent from my iPhone using Tapatalk

Have you tried this? I’ve noticed when my grounds behind the instrument cluster and by the tdm had issues my alternator would run in the yellow and I’d have wait light issues.

Cap

 

[Retiredwarhorses]

Guys, this a not an overly difficult system to understand, as a matter of fact, All glow plug equipped diesels operate on the same principle.
glow plugs
temps sensor
glow plug relay
glow plug timer

turn the key, temp sensor sends signal that its below 120 degrees, so the relay closes allowing 24v to flow to what should be 8 good glow plugs, at the same time the timer starts...after 8 seconds or so the timer expires, the voltage stops flowing constant to the GP’s. Now, depending what box you have...early EESS or newer S3 EESS, this will determine afterglow.
early EESS pulses 24v to the glow plugs for 2ins after startup, this can been seen by the dipping the voltage gauge.
S3 EESS on the other hand sends 3.5-4.5 volts to the glowplugs constant for 2 minuets, due to the low draw and it’s constant, there is NO DIP visible on the voltage gauge.

So, if you turn the key cold and get no wait light, don’t see the voltage gauge dip fast into low yellow, or even possibly red and when wait light goes out the voltage gauge should jump back to just below green, you have probably at minimum fried all your glow plugs, and throwing in new ones will do nothing too fix the reason why they were fried to begin with.
For the boxes to work correctly they need the glow plugs in the circuit, not necessarily all of them, “like 4”.

 

[papakb]

Good write up Steve. Clean and simple.

 

[M371954]

Guys, this a not an overly difficult system to understand, as a matter of fact, All glow plug equipped diesels operate on the same principle.
glow plugs
temps sensor
glow plug relay
glow plug timer

turn the key, temp sensor sends signal that its below 120 degrees, so the relay closes allowing 24v to flow to what should be 8 good glow plugs, at the same time the timer starts...after 8 seconds or so the timer expires, the voltage stops flowing constant to the GP’s. Now, depending what box you have...early EESS or newer S3 EESS, this will determine afterglow.
early EESS pulses 24v to the glow plugs for 2ins after startup, this can been seen by the dipping the voltage gauge.
S3 EESS on the other hand sends 3.5-4.5 volts to the glowplugs constant for 2 minuets, due to the low draw and it’s constant, there is NO DIP visible on the voltage gauge.

So, if you turn the key cold and get no wait light, don’t see the voltage gauge dip fast into low yellow, or even possibly red and when wait light goes out the voltage gauge should jump back to just below green, you have probably at minimum fried all your glow plugs, and throwing in new ones will do nothing too fix the reason why they were fried to begin with.
For the boxes to work correctly they need the glow plugs in the circuit, not necessarily all of them, “like 4”.

Still relevant, thanks for posting. Mark