Air conditioning 1151

[Dpas1973]

Anyone know why my rear ac on 1151 cycles on and off every 3 seconds but the front stays on and blows cold?

 

[mrfarb]

I recently got mine running, but to clarify is it the interior condenser unit cycling or the rear condenser/fan assembly? I’m assuming interior condenser. How are your pressures? Have you attached gauges? These will be variables that will need to be known.

 

[Dpas1973]

I recently got mine running, but to clarify is it the interior condenser unit cycling or the rear condenser/fan assembly? I’m assuming interior condenser. How are your pressures? Have you attached gauges? These will be variables that will need to be known.

Yes the inside evaporator and the condenser for the rear cycle on and off every 3 seconds. The front stays on and works like normal

 

[mrfarb]

Here is a wiring diagram so you know what parts are in the system. First, I am a handy tinkerer with mechanical ability, not an a/c tech- but I fixed mine with this diagram and help from this forum. I suggest checking the rear relay, and maybe the pressure switch, but first verify your a/c is charged properly. You have to hook up gauges as the first step.

 

[REF]

On my unit the rear evap runs with the rear condensers, front evap fan runs with switch. If your rear evap is cycling on and off with the condensers chances are the compressor is also cycling. This could be low on freon or a bad high of low PSI switch.

 

[Mogman]

I would highly suspect at least one of the condenser motors is stuck or "tight" pulling too many amps and tripping the 30A breaker in the battery box that feeds wire #720A, that breaker powers the rear evap and the rear condenser fan motors.
I would begin by unplugging one of the rear condenser fan motors at a time.
Edit, those wires are accessible after removing the plastic mud shield under the condenser.