Both Air Conditioners Don't Work

rgatijnet1 wrote:

dougrainer wrote:
Do you have a Factory EMS system? If so, they sometimes wire the compressors thru that shed system, so if the EMS system is malfunctioning, you get NO power to the compressors. Doug

I would think if the EMS system were at fault, no power would get to the AC units. Since the OP said that the fans are working, doesn't that mean that there is 120 volts available at the AC units? He hasn't said that the compressors try to start and can't, which would indicate something limiting the current draw.

You do not understand the EMS compressor shed system. Yes, you have 120 power to the Roof AC unit. On those AC control boards are 2-yellow wires. Those wires go to the EMS Compressor shed system and if installed and malfunctioning OR working correctly, when the yellow wires are activated will 12 volt stop the compressor relay on the AC control board from closing to supply power to the Compressor. The reason some OEM's use the optional compressor shed, is to allow the roof AC fans to circulate air when you have limited amp capacity that will not allow the compressors to run. The majority of the EMS systems kill 120 power to the complete AC. Doug