M7040 Cab heater ???

[Tin Man]

I have an 08 M7040 4x4 cab loader. we live in Banner Elk, NC and with all the cold and snow we are having, when im out feeding cattle in this mess with no heater is cold. the tractor heats up by the gauge on the dash but no heat. I move the hot to cold switch some times it starts to work but not always and some times not for long. I dont want to buy that whole switch panel and that not fix it. so has any one esle had this happen to them. Thanks

 

[Dave_eng]

Tin Man
I sent you a private message.

My M7040 is new so I dont have any issues but I do have a workshop manual and am slowly educating myself to how things work.

I offer some observations on your problem.

The heater switches on the upper cabin roof only switch low current so it is unlikely they are your problem.
These switches control a series of relays in the AC package which is located under the seat. It looks like you need to unbolt the seat to get access.

There are two relays associated with the blower operation. One for power to the blower and another for when you select high speed. The different speeds for the fan are possible by having a resistor to lower the voltage to the fan motor.

If the fan does not want to work on any speed I would suspect the first fan relay.

I am guessing that all 10 relays under the seat are the same so it may be possible to swap say the one for the AC compressor for the fan relay to see it that solves your problem.

Dave M7040

 

[Tin Man]

Sorry the fan work and the tractor heats up but only blows cold air, like it wont switch over to heat.

 

[BAP]

Check to see if there is a shut off valve in the heater lines coming off the engine block. If it has been shut off, you need to open it so the hot coolant can flow thru the heater core in the cab.

 

[Tx Jim]

Check to see if there is a shut off valve in the heater lines coming off the engine block. If it has been shut off, you need to open it so the hot coolant can flow thru the heater core in the cab.

According to Kubota parts there are no manual coolant shut off valves. I'll guess that the door under the seat that controls cold or hot air is not operating correctly.

 

[Tx Jim]

Dave
The schematic you posted appears to be for AC. Is there a section on the heater?

 

[tthorkil]

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This is from my M9540 manual, but I would guess that your M7040 system works in the same manner - this should give you an idea of what might be wrong.

 

[Dave_eng]

What I can see is that there is a temperature control motor under the driver's seat which is controlled by the temp knob on the control panel. It must move dampers to direct air to the cabin either thru an AC coil or a hot water coil.
Making certain that this motor is responding to the control knob would seem to be the first step. If it is not then one must determine if the knob is defective or the motor.
Dave M7040