DIY Troubleshooting HVAC

[rewillia]

Seeking advice,

I have a new-to-me 2018 Classic M3 RQB with the dual front & rear Dometic HVAC units.

The trailer is currently connected to 50-Amp shore power, yet I can't seem to get the rear bedroom HVAC to turn/come on even though it shows the unit to be engaged (on) in the Multiplex Control Panel. I've have checked the breakers for both units (of which are in normal on position).

The front, center unit is operating normally, but again, the rear unit is not coming on.

Any ideas on how to troubleshoot this problem?

[kittmaster]

Originally Posted by rewillia

Seeking advice,

I have a new-to-me 2018 Classic M3 RQB with the dual front & rear Dometic HVAC units.

The trailer is currently connected to 50-Amp shore power, yet I can't seem to get the rear bedroom HVAC to turn/come on even though it shows the unit to be engaged (on) in the Multiplex Control Panel. I've have checked the breakers for both units (of which are in normal on position).

The front, center unit is operating normally, but again, the rear unit is not coming on.

Any ideas on how to troubleshoot this problem?

I assume you know that each AC is considered a "zone" correct?

When you press the zone button, it determines which AC is in focus for modification.

On my 2019, Zone 2 is the REAR AC and Zone 1 is the front AC.

Please verify you have pressed zone to switch between the 2 to turn them on or off.

[rewillia]

Originally Posted by kittmaster

I assume you know that each AC is considered a "zone" correct?

When you press the zone button, it determines which AC is in focus for modification.

On my 2019, Zone 2 is the REAR AC and Zone 1 is the front AC.

Please verify you have pressed zone to switch between the 2 to turn them on or off.

Will need to check that. Thanks.

[kittmaster]

Does your controller look like this:

[kittmaster]

Sooooooooooooooo?

[rewillia]

Originally Posted by kittmaster

Sooooooooooooooo?

Nope, mine is a 2018 Classic and has the Firefly multi control panel which provides digital switching for front and rear HVAC units. I've tried both Heat Pump and AC modes on both units which can be run independently or simultaneously and the front unit operates properly on demand while the rear is not coming on in any mode or setting.

Have since called AS and reported it such that its now registered as a warranty problem to be address by the dealer once i take it in (soon I hope) for other matters including the Alde Fluid flush TSB of which I'm in que for with the Dealer as soon as they receive the new glycol.

[kittmaster]

Originally Posted by rewillia

Nope, mine is a 2018 Classic and has the Firefly multi control panel which provides digital switching for front and rear HVAC units. I've tried both Heat Pump and AC modes on both units which can be run independently or simultaneously and the front unit operates properly on demand while the rear is not coming on in any mode or setting.

Have since called AS and reported it such that its now registered as a warranty problem to be address by the dealer once i take it in (soon I hope) for other matters including the Alde Fluid flush TSB of which I'm in que for with the Dealer as soon as they receive the new glycol.

Ah ok, sorry to hear. The controller I showed is what we have and I've seen it confuse some users with the one control controls all method.

Let us know how you get through it and what they find. Sorry I couldn't help you more.