Glow / Wait light question

[Thumper580]

My wait light didn't work... I could hear the relay click inside the EESS and the light would flash for an instant...... never acted normally.
I bought a new EESS 12446779, 6110-01-395-9585 and a new glow plug temperature sending unit 12338772, 2920-01-175-7214... and a wait light...

Installed them all and... The wait comes on for 7-10 seconds then goes out, I turn the key to start and it starts right up.
However, about every 9 seconds the wait light will light up for a second then go out and I can hear a relay click... The sequence repeats itself???????

I bought new glow plugs but have not yet installed them....maybe tomorrow.

Ideas on what might be up? or will the new glow plugs solve the problem? Thanks.

 

[Milcommoguy]

Could be the "after glow" circuit timer cycling. Some software programmers/ box designers big idea to keep the heat on the plugs. Keep an eye on it (so to say) and watch the voltmeter for a dip in voltage when cycling. Should time out or stop at some point. If not you may have gremlins loose in the box.

All could be well... then again ??? NOT being a fan of PCB / EESS boxes, worst case is the CPU "hick-ups" and takes out the glow plugs. If the weather is warm may not notice any issues... until colder - winter rolls in and then, hard time starting and the gremlins coughing white smoke signals out the tail pipe.

YEP, Got to love those gremlins, CAMO and here's a stinker

 

[Thumper580]

Could be the "after glow" circuit timer cycling. Some software programmers/ box designers big idea to keep the heat on the plugs. Keep an eye on it (so to say) and watch the voltmeter for a dip in voltage when cycling. Should time out or stop at some point. If not you may have gremlins loose in the box.

All could be well...?? then again NOT being a fan of PCB / ESSS boxes, worst case is the CPU "hick-ups" and takes out the glow plugs. If the weather is warm may not notice any issues... until colder - winter rolls in and then, hard time starting and the gremlins coughing white smoke signals out the tail pipe.

YEP, Got to love those gremlins, CAMO and here's a stinker

When the wait light cycles the volt meter drops. From what I have read that indicates the glow plugs are jacked..... I'll replace them and see what happens...

 

[Milcommoguy]

When the wait light cycles the volt meter drops. From what I have read that indicates the glow plugs are jacked..... I'll replace them and see what happens...

NO No no. The voltage drop "window wiper" action of the voltmeter is an indication there is glow plug action. A full set ( of good plugs can draw 50 to 150 Amps depending on battery voltage and other variables. That's a lot of electrons making heat. Just indication of the p u l l on the battery voltage.

Added>>> it is the "after glow" cycling that designers built into the box for a sure and cleaner start on off on off on off on off. IMO more to go wrong.

Maybe all are working BUT good to test each first before cashing out. Check / test them all individually to be ready for winter.

Most important is the cycling shuts off after a couple minutes. If EVER the voltmeter does not recover from the back and forth... and stays LOW ... SHUT it off. That's a sign the "box" has not released the glow plug voltage. (could be alternator too. Just have to learn how your HumV behaves. lots of personality)

NINTY seconds of staying low... there's is GOOD chance you burned thru a $100 bill for new plugs. You will know when it started and ran fine to the parants for Thanksgiving dinner. Stayed for the home made pie and it would not start when time to go home. (one of a couple likely headaches)

That little voltmeter can tell a lot of stories to whats's going on under the hood. At night with the lights on, flash back to the 70's at a disco dance party. LOL

Always nice to have some spare HumV plugs with the bullet tops, right in the glove box.

Buy if you want. IMO I think you're OK. The test is the proof. A low LOW resistance 1.5 - 5 ohms +/- Above 5 ohms questionable & toss it.

Check each and save some bucks, CAMO

 

[Thumper580]

Everything seems fine the GP wait light will cycle for a minute or two after a cold start and then stops. Truck starts immediately...

 

[Dpas1973]

My glow plug light comes on for a second after it’s been running and not sitting for a while is that normal?


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