Tractor cab does not blow hot air when turned to heat

well the tests are simple to begin.
No car told at all , year,maker and model.
1: engine temp 180f to 200f, see on scan tool or IR thermal gun (tools)
2: hands on heater core tubes both as they pass through fire wall
and both are hot (180f) hand flies off hot. both hot is now a problem in inside the cab and not the engine bay at all,
if files here, the engine thermostat is bad.
cab.
next is the dampers for air distribution.
mode damper face or floor must to those on demand (eyeballs look)(
the heat to hot and see blend do door go hot.
the SM (USA) covers the damper tests.
we even turn them by hand, actuator off, (modern cars none told)



https://eautorepair.net/Marketing/Default.asp

First thing I would do is flush the heater core with a 4 to 1 mixture of water and muratic acid. Put it in there and blow it out both ways 3 or 4 times. Let the acid mix set for about 10 minutes before blowing it out with air. This is a cheap fix, if it works. $7 and your time. Got to say though, it only works about 30% of the time. The other 70% is to remove the heater core. Dodges/Chrysler su(k. To get to the heater core, you have to drop the steering column, and remove the entire dash. Then remove the heater/A/C plenum to remove the heater core. Buy a manual to do this. Way to many hidden screws and bolts. This job costs about $800 at a garage. It takes about 8 hours to do, if you know what your doing.

HVAC? the cab heater is dead or weak.?
1: does fan blow?
2; is heater lever to max.?
3: is mode lever at heat?
4: does engine reach and hold at 180F or more? no guess, this really is the first thing, (mechanics) that must work first.

no engine heat , gives you no cab heat. ever.

are you handy ,or just want wild guessing
if handy ,all ways it can fail are here.
the system is simple, its only a heat exhanger.
but is complex do to modes.
here is the list
a mech, knows its 3 reasons (pure physics)
1: engine not hot.
2: coolant not flowing in cab rad core.
3: air not flowing through cab core.
just 3 possible, in physics.

the tests are simple.
http://www.fixkick.com/AirCond/heater.html

say what dont work.
ok the blower blows, and for sure on high.
so what do you want , and where.
heat to cab?
cold air conditioning to cab?
does not work, ok
lets do 1. no heat to cab,
blow fuse is 1st . check all fuse. (see glove box operators guide)
if no heat:
check engine heat, is it 180F and holding
check cap heater core hose, in heat mode are both hot. ?
if both are hot you have heat to the core and is a damper failure
in the heater box (or controller)


this car is a frankencar.
Honda Passport was a badge engineered version of the Isuzu Rodeo released in 1993 and sold by Honda in the United States

did you try changing thermostat

What was your temp gauge reading on the vehicle when this occured?
It could be a small plastic blend door in the dash that is operated by a small motor that when you turn your switch to hot the door moves to allow the heat from your heater core to be blown through ducts into your cab. Sometimes these can be calibrated sometimes he plastic door brakes. BUT i would start by bringing the vehicle up to operating temp first and checking it then.

Check for correct coolant mixture. Also you could have a thermostat that is stuck completely open causing it to flow straight threw the engine block, cylinder heads, heater core, an radiator without stopping long enough to heat the coolant up to provide cab heat. It could also be a clogged heater core. Or a blend door on the HVAC box that is not allowing the heater core door to open. Hope this helps.

Sounds like hose got dislodged. Check under dash & fix. (If you can even get a hand in that area)

replace the blower motor speed control resistor

I think you should check the air manifold on the control panel and try to find any broken or loose hose.
In addition, check the heat/cold dial knob, under the dash, there is a panel selector for hot air or cold air.
Also check for any broken vacuum hose under the hood.