Hmmwv start box yellow label Nartron help

[MarkM]

Hello all,

Changed out my yellow label start box. Barrel relay was jammed on so it was constantly sending 24v to the plugs. I have another known good box same yellow label Natrona but could someone please explain this afterglow function please? Mine comes on at 20v then the dash light goes out and the truck starts immediately but then about every two or three sec it will toss 20v for a half sec then after two sec it will toss 5v to 20v for around a half sec or less. Plugs all seem to still be fine and I can see this voltage pulse on the dash volt gauge. I am just taking baby steps as I don't want to go through this hell again. Any assistance would be greatly appreciated.

Mark

 

[Coug]

so afterglow is it's sending short bursts of voltage through the glow plugs to keep them warm. They already warmed up during the main cycle, and if you continued to apply constant voltage they would overheat and burn out. The pulse is just one way to keep them warm, but not overheat them.

Newer boxes apparently do the afterglow by reducing voltage.

Just 2 different ways to achieve the same effect.

This is perfectly normal.