Cabbed HVAC Controls

[coolnick73]

I have a Branson 4520C and the heat doesn't work. I had a previous thread and I did the suggested troubleshooting by checking the cab air filters and ensuring the coolant is at the proper level. When none of that worked, I unscrewed the HVAC control panel and had a look. The unit has power (all the lights work), it will kick on the AC compressor, the fan works, and the fresh air door opens and closes. When I turn on or off the Heater switch, I see nothing moving or hear any sounds, also when I adjust the heat blend control, I don't see movement or hear noise. I think this is what should be moving . It looks like the top is the valve that opens the coolant flow and the bottom is for the air door.

Do you think I have a bad control unit? If so can I override the malfunctioning part and manually open the heat valve and move the air blend door without breaking something? This is the second time I have had a issue with the HVAC controls as my AC stopped working a few summers ago (it was replaced on warranty.) If the controls are the issue, has any one opted to replace it with an automotive one (Ford/GM/Mopar)?

 

[LouNY]

Can you check voltage from the heater switch when you turn it on?
When you rotate the temperature knob can you monitor the voltage from it?
Can you feel the heat control valve try to actuate?
Or monitor the voltage signal to it.
Looking at your pictures I would agree that you are on the right track.
I wish the service manuals and wiring diagrams were available on line.
I expect that you can purchase one for your tractor, my 8050 it isn't available for any price, supposedly not printed.

 

[ptsg]

Can't help you with your issue but here is the service manual for your tractor. Maybe there is some valuable info that might help you.

Branson 20 series service manual

 

[LouNY]

Can't help you with your issue but here is the service manual for your tractor. Maybe there is some valuable info that might help you.

Branson 20 series service manual

ptsg;
That is a good manual for the 20 Series.
Does Branson sell the 8050 over there?
They have dropped that model here and my dealer tells me that there is not a service manual available for it.
If one is available over there could you let me know where and how to purchase it.
Preferably in English.

Thanks
Lou

 

[ptsg]

I'm aware of your situation LounNY and I've actually tried several times to find any good info on a manual for you. But seems like an impossible task.

The only thing I've come with up with is the Operators manual which is not really helpful for repairs.

Those tractors were not sold in the Western Europe as far as I'm aware. They just recently started selling the higher HP tractors here with the K78 model that is the same as the 7845.

I've seen a couple 8050 over in the Eastern Europe, mostly in Russia, not sure if they can get any manuals for it. Does it have the air compressor that most Eastern Europe tractors have? If yes, then it's sold there.

The 7845 looks like the upgraded version of the 8050? If so, might be easier to find a service manual for that instead of the 8050. I have the operators and parts manual for the K78.
Mostly differences seems just cosmetic but I've never seen any of those two in person. I wouldn't imagine that the mechanics and electrics would change that much.

I'll keep searching though.

 

[LouNY]

Thanks for the info,
I have downloaded a service manual for the K78 series which seems to be close.
When I got my 8050 the 7845 was also available and I compared the two,
they had the same engine, but different transmissions and rear ends.
The 8050 was a thousand pounds heavier with less gears and only a two speed pto,
three rear remotes with two for the 7845. The front axle seemed to be heavier on the 8050
also.
8050 has a 3 ranges and a 4 speed trans with a 540 and 540E pto,
7845 has a 4 range and a 4 speed trans with a 540, 540E and 1000 pto in a lighter package.
Also no air compressor on mine.

Thanks for looking

 

[Texasmark]

My 6530C came with a ball type (90 degree turn) coolant fluid shut off valve on the left side (sitting in the seat) just aft of the radiator. Off is perpendicular (crosswise) to the hose...hose is about ｾ" or so in diameter. Purpose is to ensure you have max AC in the summer without any accidental bleeding of radiator fluid through the heater core of the AC system. Only thing you have to do is remember to move it (which I usually forget) as the seasons change.

 

[coolnick73]

Looks like I will be removing the roof off the cab. Thank you ptsg the service manual is helpful. I will try to remember to take some pictures when I am removing the roof.

 

[coolnick73]

Removing the cab roof is rather easy if you don't take it off all the way. There are six studs that hold the roof onto the frame. You don't need to take to top nut and rubber washer off. There is a nut and a large washer underneath these. This will allow you to keep the red and black roof components together and then you can just tip the roof to one side to gain access.

Next I just unattached the linkage to the coolant cutoff valve and opened it manually.


Does anyone know how the temperature control works? In the service manual it talks about a blend door in the troubleshooting section, but in the pictures and exploded drawings there is no indication that there is a mechanical blend door. Could it use the actuator to throttle the engine coolant valve to adjust the temperature (which wouldn't explain the on/off heater toggle switch)?

 

[LouNY]

Interesting pictures, you definitely found the water valve.
Is there a blend door on the far side of the box with the heater core in it?
I looked thru the 7845 manual and the 8050 parts pdf and the manual mentions the same blend door,
but I don't see it in the parts breakdown.
Good luck