HMMWV glow plug/controller question(s).

[pigdog]

Was having trouble starting the Beast on cold mornings. Wait light comes on for approx. 8 seconds and goes off, but will crank and crank while putting out white smoke until it eventually starts.
A multimeter showed that power was going to glow plugs so I replaced the glow plugs.
Still having issues.
New plugs fail resistance test; pulled one and its already swollen.
Further testing shows that no matter how long I let the truck run, the smart box is always putting 24ish volts to the plugs, which explains why they have failed already.

So, I'm guessing it is time for a new box (it is a yellow labeled Natron).

Is there anything else I can test before throwing money at a new box and hope it fixes it?

And what else does does the box do? I read that it controls other functions but no one seems to say exactly what those functions are, and say that's why you shouldn't just wire up a manual control for the glow plugs.

Also, will it damage anything to pull all the glow plug wires until I fix it?

 

[Retiredwarhorses]

Your box is bad...the Glow plug timer is shot, this is not uncommon, replace the box with an S3 EESS, TSU and new glow plugs…

 

[Milcommoguy]

Happens every winter to a Humv, or anytime. I have written many post to this. One can go QEM with the latest S3 smart box. Bring your wallet.

Glow plugs most likey toast. 24 Volt for more than a minute and POOF ! Another 90 bucks and that may not be the final fix. Cold weather, white smoke, more cold weather, hard on batteries and a starter $$$$ and don't get the big idea to using starting fluid IMO. Engine $$$$$ The little computer grelim in the"BOX" is reaching to your wallet

I am not a fan of the overly engineered and costly "Box" as in generic to the system to replace.

Been there, didn't do that. CAMO

 

[87m998]

I am interested in doing this mod, my smart box hasn't failed yet would like to get ahead of the game.
thanks

 

[pigdog]

Well, before I get to far with this, I need to change my voltage regulator, which likes to spike after starting and may have caused my smartbox to go bad in the first place.