Trans air. Condenser fan relay location help

[BigAlFlorida]

I’m working on a 2012 Chevy 3500 van chassis with an el dorado shuttle bus conversion rear. Having an issue of the condenser fans staying on after the key is turned off. I searched and this sight gave me some great trouble shooting advice. The thermostat switch in the dash is functional and I cannot currently get the problem to show itself. I’d like to locate the fuse/ relay panel for the rear trans air unit. Any ideas on where it might be hidden? There is a panel above the driver seat but it doesn’t seem to service the rear hvac in any way. I’ve checked the perimeter of the bus underneath with a light and mirror and have not found any relays or fuses. The wires from the switches go into the firewall or I lose them in the under dash spaghetti. I have yet to remove the wall panel behind the drivers seat or taken the cover off the rear roof mounted unit. Any ideas on where to look? Thanks in advance.

[Rucker]

Is it possible that the fan runs even after the rig is turned off if the lineset temperature is still too high?

[BigAlFlorida]

I considered that but the thermostat switch when turned all the way to the left. There is a click and when tested with the multimeter has no continuity in that position. After reinstalling the thermostat switch the issue has not re surfaced but according to a similar thread on this forum. After the switch there is a really for these fans somewhere and I would like to find it in case the problem resurfaces. Thanks for the reply.

[BigAlFlorida]

I will also add that this is a trans air unit and I have tried to call there numbers listed on the equipment but seems the number is not valid anymore

[cadillackid]

Trans/AIR normally locates their relay panel in a box under the bus... on my red bus its actually oddly out in the open.. and yeah things get wet and need rep[laced on it..



theres no thermostat switch on thew Trans/AIR units.. the condenser operates anything the compressor engages.. on a van cutaway that can be when the rear unit is off if this is a Tie-in system (90% are).. so if you are using only the front A/C, front Defrost, front Bilevel your compressor can come on.. (thats controlled by the original Van selector switch (looks like a car A/C)..)


the condenser fan should never run when the bus is turned off so its likely as you think, a stuck relay..


id look for the panel in the battery box, sometimes in a box on the back deck.. ive found them under the bus.. follow the wiring harness from the under-body condenser it should lead you there to it...



Trans/.AIR is still in business and will have that whole A/C system logged in their systems by your bus VIN.. and may even have service documents for you if oyu cntact them. I have bought parts a couple times from them for mine..

[BigAlFlorida]

So I’m back working on the bus today. I’ve combed all underneath for a relay/fuse panel and have found nothing under the vehicle or near the secon battery location. There is definitely a switch for fan and a thermostat switch just for the rear unit working separately from the controls for the vans factory unit. When functioning properly I can turn the rear system off with either switch being moved to the off position. Included photos of switch. Should I start removing interior panels to hopefully locate the relay panel. The wires from the switch I lose track of at the firewall and the wires from the condenser fans run in a channel between the body and frame and even with a mirror I lose them shortly after I start following. Thanks again for everyone’s help on this.

[BigAlFlorida]

Also I made a mistake. It is not a trans air system. It is act by pro air and there phone number goes nowhere. Sorry for the confusion. Photo of ac tag for reference.

[cadillackid]

I use the CS3 condensers on all mine. that tag is simply for the condenser. ProAir LLC is gone.. ACT used to be their own company till ProAir bought them.. on my ProAir systems,, it ewas recommended to me t omount the relay boards either in the engine compartment on the firewall or behind the bus switch panel if there was room..



is the inside unit marked as an ACT also? or does it say Trans/air?