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.

 

[thoner7]

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.

Where did you find that diagram? The only Air Conditioning TM I’ve seen so far is for the Red Dot style

 

[Rpaint82]

waiting on my 1165. How bad is the demilitarization process on the AC units? Any idea what I should expect? I assume all the lines will be cut.

 

[BKubu]

waiting on my 1165. How bad is the demilitarization process on the AC units? Any idea what I should expect? I assume all the lines will be cut.

I am unaware of any demilitarization of the AC units. Mine was intact and functional.

 

[Rpaint82]

awesome! maybe mine will be the same. I've heard of them cutting the lines. they put a hole in my oil filter (I was told to drain the oil) God only knows what exactly Ill be dealing with until I get it. 1165 ( not in running condition) slant back 2009 6.5 T. Paid $4k Hopefully worth it.

 

[thoner7]

awesome! maybe mine will be the same. I've heard of them cutting the lines. they put a hole in my oil filter (I was told to drain the oil) God only knows what exactly Ill be dealing with until I get it. 1165 ( not in running condition) slant back 2009 6.5 T. Paid $4k Hopefully worth it.

Auction? That’s a good price but, there may be some issues to fix

 

[Rpaint82]

Yes auction. I'm planning on there being some issues for sure. What I know from pictures, missing speedo, thermostat housing was removed, hole in oil filter, missing break fluid reservoir. I assume it was used for some parts. Body, interior, steering linkage looks good so I took a chance. Worst case will be an LS swap sooner than later.