Quote:
Originally Posted by samalf23
Thermostat is the original does not display temp - checked to see if thermostat was getting voltage and it is. But fan will not run so not sure at this point if it is the Run or Fan Cap or the control box or all three. I have parts breakdown but no manufacturer troubleshooting steps/guide. The caps are relatively inexpensive but not going to get both if not necessary.
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12 volts to the thermostat is a good start. For it to fire up the AC, it will send 12 volts to the compressor line and 12 volts to the fan line. Since you measured 12 volts coming into the thermostat you could measure it going out on the control lines.
The AC motors are 2 separate units and probably have their own start caps. 120 volts is required for either to run. If neither will start I would look for something in common with both - 120 volts and thermostat signal to them.
You may need to measure voltage inside the AC to make sure you have the 120 volts getting there and also the 12 volt "turn on" signal. If you can get the model of AC you may be able to get the manual from the manufacturer's web site. It should show the wire connections and may even have a troubleshooting section.
My son has an AC unit in his 5th wheel that had an old analog thermostat. I bought him a nice digital one and went to install and found out it operated on 7 volts instead of 12. Not sure what system you have but if you measure 12 volts at the thermostat it is the newer style, at least compared to his olf one.
If you look at the control board inside the AC, which you may be able to see after removing the bottom grill (if you are lucky), look for any wires that may have come loose.