Coleman AC issue

[jamesc]

I have an issue with one of my two coleman roof top ac units. The units are on a 97 Adventurer and probably the orginal units. The front works fine and the rear did for a couple of years. Then the rear no longer worked. If I set the thermostat to cool all I hear is no fan and a slight humming sound from the unit. I switched out the thermostats with no luck. Checked the breakers and made sure I was operating off a 50 amp service. No go. Any ideas will be appreciated.Thanks

[RV Wizard]

jamesc, welcome to iRV2.com. We are glad to have you join us here and we look forward to reading of your adventures and experiences. I am sure you will enjoy us.
The compressor is not coming on or if it is it has quit pumping or out of refrigerant.
Are you experienced in using a multi meter? If so, are you able to get on the roof to do some diagnosing? If so and you want to proceed, give us the model of the unit you have and we help you find the problem.

[Gary RVRoamer]

The fan should run if the t-stat is ok and there is power at the a/c unit. I'm thinking that either the fan is stuck, fan motor dead, or a circuit board problem that is not starting the fan at all in response to the thermostat call for cooling. Typically the fan comes on and then the compressor kicks in a few moments later. If you are not getting any fan, you are not getting to first base..

[Triker56]

It could be the fan motor or just the fan capacitor.

Try to give the fan help to start turning by hand when switch is turned on.
If it will keep running then the capacitor is bad. Replace it.

If fan will not run with help then replace fan motor & capacitor.

After you get fan running right. If compressor hummms and doesn't start up. Replace capacitor on it.

Coleman Parts List You will need your AC Series number

[jamesc]

Thanks for the help. I am sitting in the mountains of northern New Hampshire and happen to have my meter. If mumma lets me be tomorrow I will try these ideas .Thanks again