Retrofitting OEM heat into BJ40 - questions

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Sep 19, 2015
Durango, CO
Good morning fellow diesel degenerates :flipoff2:

I'm starting the process of putting together the heater components to add heat to my Costa Rican 75 BJ40. My assumption was that many parts from a US Spec FJ40 would swap into my BJ... Save for any electrical or diesel-specific parts.

My question to all of you - what parts are 24 volt-specific and of those, how difficult would it be to 'convert' them to 24v. My thoughts are the blower motor is definitely 24 v specific, but what about the heater box? Before I buy a bunch or parts I can't use, this information would be good to know. :)

With that being said - is it doable to convert the 12v parts to 24?


Has any of you fine ladies and gentlemen (trying a different tact here) used a potentiometer to reduce the voltage from 24 to 12 prior to the heater compenents to accomplish this?
I looked into using dropping resistors for a 12V radio. Ended up getting a dc converter.
I think using resistors to drop voltage would generate a lot of heat.
Well... it looks like @ToyotaMatt came to the rescue for me. He had a 24 volt blower motor that I took off his hands and it's on the way. Since mine has the ultimate "heater delete" (no hole at all in the firewall ala LatAm/Columbia Spec) another MUD vendor @kevos37 is sending me a cutout piece of sheet metal from a 40 US Spec firewall, that I'll get that put into mine. For the rest of the stuff, I'll just be able use FJ40 US Spec stuff which I'm close to acquiring. Be part of my "winter with BJs and 40s" campaign.

On the way.. my spending spree has me flat busted, so I guess now it's time to start wrenching :)

FIgured try to do this as correct as possible and stick with 24 volt stuff all the time.
I agree with using 24V whenever possible.
I renamed the thread on this, as now that I've overcome the 24 volt blower motor issue, by just getting the right part, I'm curious as to opinions on where I should locate the pull knobs. I only have two holes for the Fan Pull, Fresh Pull and Warm Pull knobs as the fuel cutoff pull knob is where the Warm Pull goes. I guess I'll just route it to another one of my blanks.

Anybody else installed an OEM heater into a LatAm spec BJ40 is welcome to share any tips or tricks here.
And I'm baaaack... My collection of parts continues and I need more guidance for my BJ40 with the B powerplant

24V blower motor acquired as well as heater box (from a 78 FJ40), shut-off valve, heater duct, defrost hoses (with side defrosters!!) and the firewall piece that will need to be welded in.

Here is what I think is left to acquire:
  • Resistor for blower motor to enable low/high functionality
  • Hoses that go from heater box through firewall into engine bay
  • Hoses that connect up to existing coolant lines
  • Any fittings associated with above coolant lines
  • Pull knobs ( 24V fan pull, heat pull, cold air pull) - I believe the 24V fan pull knob is the only one where a US Spec 2F 40 knob won't work.
So... I need some Help... Beyond sourcing the remaining parts (thanks again so far to @ToyotaMatt, @kevos37 and another MUDer whose handle on here, I don't know). SOR's website is helping some, but there isn't much in the way of diesel heater diagrams. And I don't want to buy anything from SOR if I can help it other than perhaps a heater box refurb kit.

If anyone has some pictures to share of any LHD BJs that have heat and how the hose routing goes and such, that would be appreciated. Still a ways out from putting this into action, but I'm much closer than I was a couple of months ago.
24v resistor is available from cityracer

member on hear from McClure BC, often seen on the Mud diesel classified section should have a stash of 24v parts
Asa lot, if not all of the bj40’s
in Canada were 24v

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