# 5100E HVAC Blower Speed Issues



## Sterling6.7 (Jul 11, 2017)

Hello,
I have a 2018 FT4 5100E with a cab and this morning the blowers would only operate on high speed. I did some poking around with the switch and then also in the expansion chamber with a 12V test light, not a multimeter. The switch seems to be passing voltage on the different terminals as I rotate the switch, but the blowers do not run on the lower speeds. In the expansion chamber, there is a part that has some coils on it that would seem to control the fan speed, based on resistance, and this seems to be physically in one piece and passing voltage. At the moment, I am out of ideas. The visible wiring seems to indicate that there is a component someplace else that might need to be looked at. Does anyone have any thoughts? Thank you in advance.


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## Sterling6.7 (Jul 11, 2017)

Did more metering on the blower resistor and it seems to be possibly bad. Looks like it is either the switch, (2) relays, the resistor and the blowers.


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## Cozyacres (Jul 16, 2009)

Sterling6.7 said:


> Did more metering on the blower resistor and it seems to be possibly bad. Looks like it is either the switch, (2) relays, the resistor and the blowers.


I have found on tractors, trucks, etc, when the blower only runs on High it is usually the resistor, occasionally the speed switch


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## ttazzman (Sep 29, 2019)

I second the resistor


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## Markpnw (Dec 27, 2019)

Most like likely the resistor or bad wire shorting. How many hours on the tractor?


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## Sterling6.7 (Jul 11, 2017)

2100 hours


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## PaulN (Mar 4, 2014)

I had the exact same problem this spring. It was the resistor.


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## Sterling6.7 (Jul 11, 2017)

Perfect. Thank you


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## Sterling6.7 (Jul 11, 2017)

The resistor was the issue on this. Thanks for the suggestions.


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## Gearclash (Nov 25, 2010)

I have seen some people say that if a resistor goes out, there is reason to suspect that the fan motor has a problem causing excess current draw, hence the resistor failure. I can’t say that is always the case as I have a tractor that most likely has a toasted low speed resistor; its been that way for 10 years and the fan motor is still working.


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## Sterling6.7 (Jul 11, 2017)

I could believe that and hopefully not though.


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## PaulN (Mar 4, 2014)

The reason my resistor failed was from over heating due to low airflow. After taking the air box out of this 20 year old tractor, I found the AC "radiator" was covered with a mat of dried dust. It came off like a piece of felt. Now it has tremendous airflow.


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## Casey Brooks (6 mo ago)

Sterling6.7 said:


> Hello,
> I have a 2018 FT4 5100E with a cab and this morning the blowers would only operate on high speed. I did some poking around with the switch and then also in the expansion chamber with a 12V test light, not a multimeter. The switch seems to be passing voltage on the different terminals as I rotate the switch, but the blowers do not run on the lower speeds. In the expansion chamber, there is a part that has some coils on it that would seem to control the fan speed, based on resistance, and this seems to be physically in one piece and passing voltage. At the moment, I am out of ideas. The visible wiring seems to indicate that there is a component someplace else that might need to be looked at. Does anyone have any thoughts? Thank you in advance.





Sterling6.7 said:


> The resistor was the issue on this. Thanks for the suggestions.


I have the exact same problem on my 5100 E where did you find the resistors? Thanks so much for your help mine is stuck on high speed.


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## Sterling6.7 (Jul 11, 2017)

I will see if I can find it


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## Sterling6.7 (Jul 11, 2017)

TRY SJ31007


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