Rv ac

[teosails]

My ac is an Airxcel 15K ducted system. It is 3 years old. When I installed it, I added a
Micro-air soft start. This has been working perfectly for 3 years.
Suddenly, no matter the fan speed switch position it only blows at low speed. I set it in low and went to the upper control panel and disconnected the high speed terminal… no change. Re-connected it. Disconnected the low speed terminal and fan stopped. Re-connected it, fan started. Set the speed switch to high, disconnected low speed terminal, no change. Re-connected and disconnected the high speed terminal and fan stopped. Re-connected and it came back on.
In both cases it only ran at low speed.
I don’t know how to test the fan motor, the capacitors or the easy-start to find the problem. Any help would be appreciated.
Thank you,

[teosails]

I did switch the low and high speed leads and I think it runs a little faster, but not noticeably so.

[wa8yxm]

HAVE you tried connecting the fan's high speed lead to the low speed terminal.. I'm guessing control fail but motor fail is possible as well. The start caps.. NOT the problem.

[joebedford]

More likely the thermostat.