CK30 HST heater fan problem

[Retired guy]

Last February my cab heater stopped working on high speed. Thinking it was the switch, I replaced it and still no high speed.
Knowing I had to remove the roof, I put it off until now. I got into it yesterday with meters, jumpers, etc. Switch is good, continuity on both positions.
switched relays and still no hi speed. Spent an hour today at the dealer with the service manager who suggested some things that I
had already done. There is a plug with two connectors going into the fan motor that is screwed into a plastic plenum so there has to be a ground
somewhere. We both question a resistor somewhere in the circuit BUT he does not have a cabin schematic. There is mysterious connector on the
edge of the fan housing that he could not identify. I would like some suggestions or a link to a schematic if any one has one. I asked about
replacing the fan motor...you cannot buy one..Kioti only sells the complete heater @ $575. There are only 3 screws holding a simple 12 volt squrrel
cage fan. HELP

 

[joe48]

do you have an electric motor shop in the area that rebuilds/repairs automotive stuff, like starters, generators, alternators etc. Call them and ask if they can repair your fan motor.

I have the same problem with my heater fan on my CK2510 cab. The only reason I haven't bothered to fix is I don't need high speed and barely need low. The heater puts out so much heat after 15 minutes, I have heat control valve on minimum, and windows all cracked and usually in my shirtsleeves even in 20f weather!

 

[34Willys]

If your blower motor is spinning, it's probably ok. Don't remove it for a rebuild. In most systems, the blower motor resistor pack is the problem. Disconnect the blower motor and apply battery voltage directly and you should get full/hi speed. The motor gets full power from the relay, then it's stepped down by the resistor pack to ground. It's usually located in the air stream to keep it cool. That's probably what the 'mystery connector' is.
Hope this helps.
Patrick

 

[Kioti Paul]

I have attached the schematic for my DK45 (about a 2008 model). I have no idea if it is similar to your CK30. The heater switch and motor are highlighted.

At least for this particular model, there are no relays involved. It does indicate three connections to the motor (2 wires from the switch, and the 3rd is ground). There is a resistor, which is used to reduce the blower speed. If there was anything wrong with the resistor, it would affect the low speed; not the high speed. The motor only has one winding, and since it runs (normally???) on low speed, that indicates (to me) that the fuse, power wiring, motor, and ground are all good.

If we assume the switch is good, that seems to leave only the wiring which runs from the high speed terminal of the switch, to the fan motor. On my schematic, it is just one wire; no connections/splices except at the switch and motor (or resistor). This will be a very short "run", just the distance from the switch to the motor.

This seems like a very straight forward problem that anyone with a Volt Meter / test light should be able to trace out in just a few minutes.

The fact that it stumped a dealer's shop would indicate that it is much more complicated than my schematic would indicate.

Good Luck!



PS I found a "detailed" description of my (DK45) heater only system, so I have added that page as an attachment.

 

[Retired guy]

Thanks a lot-as soon it cools off a little (the garage has a metal roof) I will take the cab top off and try again.

 

[Retired guy]

Thanks for the info--your explanation answers the question where is the ground ? I could not find how the motor was grounded in a plastic housing.