Coolant Heater Diesel Fired M939 and others

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coachgeo

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Been doing a lot of research on retrofitting a 939J24 coolant fired heater into my LMTV. Coming across a lot of M939 information and just wanted to share. So not to rewrite everything, See the Duece Mods and Hot Rodding thread at

https://www.steelsoldiers.com/showthread.php?15643-Deuce-Arctic-Heater-Info-Compilation-Thread

Page 6 Post #57 and page 7 get a good bit into M939 info. Previous pages of that thread offer great general and deuce info as well as links to PDF's etc. that will help one understand the concepts behind how these work and are typically wired etc.


QUESTION: Anyone have or no where to get wiring diagrams of the Coolant Heater Control Box on the M939?

939J24 Coolant Heater Control Box M939 Trucks



  • NSN# 2540-01-125-6154
  • CAGEC# 19207
  • P/N# 11669705


https://www.nsncenter.com/NSN/2540-01-125-6154
 
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74M35A2

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cranetruck has tons of experience with nearly all forms of fuel fired heaters. gimpyrobb has more parts for these things than the companies that made them. Both great resources.
 

Mos68x

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BA53ECBE-F15B-4143-9B08-65DD2225E583.jpg

Found this on eBay, hope it helps. I think I’ll buy one of those for my truck, but I won’t get it from this seller though.
 

74M35A2

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*fingers going faster than brain, my response was not directed toward coolant heaters*
 
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sassriverrat

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@CoachGeo

Why did you choose this heater versus something newer/more modern? How did you controls end up working out?

Thinking about doing the same and I have a good deal lined up on a NOS unit ($150 before shipping) but I've been torn...waiting to hear back if it has a circulation pump (it's mounted in a battery-box mount) and still torn about getting a bigger unit. Also waiting to hear back from @gimpyrobb has he has a shower unit and I was planning on using this with a 6 gallon calorifer (hot water tank with a heat exchanger for dual heating options) to provide shower hot water.
 

coachgeo

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sorry I've not installed yet...... I grab things when the sale price looks right to try to lower my overall expenditures.

as to why... cost..... the espair etc. are just to expensive though of course prices are now dropping on them.... go figure.
 

sassriverrat

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Hmmm....Do you think the unit is repairable/maintainable? I'm so on the edge of buying one but again, just waiting to hear from gimpyrobb- but the issue I have with much of the new stuff is the inability to fix it. I was told by a tech that the SW is fine until it's not, and then it's a lot of hair pulling....but I wonder if the espar is even repairable of if it's got to be shipped out/flat out replaced.
 
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