Hvac issue

Shelton · 01-01-2022, 04:43 PM

Just picked up a 2019 fuzion 369 with in command. Everything works as it should except for zone 2 on hvac which is the ducted a/c and furnace. I’m showing temperature readings on them and have checked breakers and fuses. Neither a/c or furnace will make any noises or even try to come on. Tried off my app, on generator power, and shore power. Zone 1 and 3 work flawless. Any insight on what to try? Previous owner said it worked fine for them but camper had been sitting for a few months. I’d rather not have to take it to a dealer if I anyone has any solutions? Thanks

**chuckster57** · 01-01-2022, 05:31 PM

Try disconnecting from shore power, then disconnect the battery. This might reset the BCM, then reconnect the battery and then shore power. Otherwise it may be a communication error between the in command panel and the zone 2 controls.

Shelton · 01-01-2022, 06:56 PM

I have tried this a few times and haven’t had any luck. Being it’s both the furnace and a/c I figured it has to be an issue with the in command side of zone 2 just don’t know where to start on the can bus

**chuckster57** · 01-01-2022, 07:32 PM

If you have a ceiling plenum, you can remove it and the control box will be in the return duct.

Shelton · 01-01-2022, 07:35 PM

Will they interchange between units to test?

**chuckster57** · 01-01-2022, 07:44 PM

I haven’t had that much exposure to the in command system, but I suspect there is communication cables all connected at one point. Dometic units have dip switches to designate zone and functions under the roof cover, inside a box on the curb side.

Member ChuckS is the in command guru IMO, you may want to contact him, it may be the “gateway”.

ChuckS · 01-01-2022, 08:29 PM

Since you have 3 roof A/C units with in command the routing of the CANBUS lines to control all three is

In command BCM to Zone 1
Zone 1 is piggy backed to Zone 2 via 4 wire telephone cable..two wires used for 12 volt power and two for CANBUS HI/LOW signals

From Zone 2 another telephone line is piggy backed to Zone 3 via another 4 wire telephone line. 2 wires for 12 volts and 2 for CANBUS

If the gateway or control module for the ZONE not responding is bad then the BCM can’t send and receive signals to that Zone

Also.. you have 3 A/C units which means you have a Power Share module in the system to share 120 volts power amongst the 3 roof units .. if this is not functioning then that may be also something to look into

Link for your power management box…

https://www.trekwood.com/products/12...re-For-3rd-A-C

Shelton · 01-01-2022, 09:47 PM

So the gateways should be up in the a/c around return ducts correct? Can I switch the paddle switches from zone 3 to zone 2, move the gateways to the a/c number 2 to test if the gateway is bad that way? Also the power distribution box is what cycles between the a/c’s being that 3 a/c’s can’t run off 50 amp right? Being it only has 1 furnace I figured if the distribution box is bad, it would only affect the a/c since furnace should have its own power supply and blower. That’s what leads me to think it’s the gateway that’s bad or am I not thinking this through right?

ChuckS · 01-02-2022, 06:08 AM

Yes - you can do all this gateway swapping but you need to find where the TERMINATING resistor is at in the LAST gateway...

You can move the gateways around for TS purposes understanding you need to DO THESE STEPS after you swap gateways...

1. move the terminating resistor from the original #3 gateway when you swap #2 and #3
2. Install that terminating resistor in the NEW TEMP gateway #3
3. Set the dip switches for both gateways to reflect their proper function.. which means each dip switch on those two gateways you move has switch selections for 1,2,3,4
.... this identifies which gateway zone each box is assigned to

NOTE - do all this swapping with BOTH shore power and battery power removed

WHY? the roof A/C control modules have 12 volts DC present on them when either shore power or battery power is applied

After all swapping of gateways is completed then apply battery power and then shore power

REBOOT the BCM one more time..

WHY? The BCM "should have reestablished" CANBUS after you applied 12 volts DC to the unit BUT rebooting the BCM will make SURE the CANBUS looks back out at those gateways and identifies what is "In the chain" of devices

Terminating resistor - why is there one in the last gateway in the system?

Answer - this terminating resistor - which is simply a 120 ohm resistor wired to a plug and then plugged into the LAST GATEWAY in the loop ESTABLLISHES the "END OF LINE" in the CANBUS circuit

Hope the info I wrote makes sense to you... CANBUS is a simply comm line that sends either HI or LOW signals back and forth to each item in the CANBUS loop

*** GATEWAY locations - typically the gateway will be EITHER mounted inside a return duct or if ducted system like mine then the gateways are actually mounted up inside the Roof A/C unit...
The factory loves to stuff them inside the fresh air duct that is in the actual condenser compartment area which will have a plastic shroud covering it... Remove the shroud and if you see a bunch of wires stuffed down into the duct then gently pull them and you will find you gateway

Shelton · 01-07-2022, 03:46 PM

Okay finally caught a break in the weather and swapped gateways. That didn’t do anything but make some 3 not come on at all or read temp on the in command. So now I have no zone 2 or 3. Cycled the power off shore and battery power both still same results. No zone 2 or 3 now

ChuckS · 01-07-2022, 04:03 PM

There should have been a terminating resistor in Zone 3 gateway.. if so did you remove it from original Zone 3 gateway when you moved Zone 3 gateway to Zone 2 old gateway location and THEN install the previously removed terminating resistor into the gateway you moved from zone 2 to Zone 3?

Also.. there should have been a set of dip switches in each gateway (typically 4) and these must be set properly to identify which zone the gateway is set to

After making the gateway swaps WITH dip switches set properly and terminating resistor installed in the LAST Zone gateway a power down (shore and battery) should then let the system talk to all connected zones and establish new gateway link

Shelton · 01-07-2022, 04:32 PM

Yes I did all of that, I’m not reading a temp in the zone 3 now. Still no furnace a/c, or fan whatsoever. No clicking noises from any of them. Zone 1 works still but nothing after that. What if I move resistor to zone 2 to eliminate zone 3?

Shelton · 01-07-2022, 04:42 PM

After updating the system I’m getting error code e1 and e8 on the dometic. Any input on those codes?

**chuckster57** · 01-07-2022, 08:01 PM

This should help

https://thermostatguide.org/dometic-...oubleshooting/

ChuckS · 01-08-2022, 07:23 AM

Quote:

Originally Posted by chuckster57

This should help

https://thermostatguide.org/dometic-...oubleshooting/

Great link for him... he has a zone not configured correctly and the CANBUS line can find EOL (end of line) plus the devices in the line are not configured correctly with the dip switches... either on the gateway or Zone control box board

Shelton · 01-08-2022, 02:48 PM

Dip switches are set right, double checked them. I’m thinking my gateway box is bad and causing my issue because now it is throwing 1, 2, and 8 error codes. Zone 2 is now working fine after update. So the box I moved the problem followed the box.

M&M2 · 01-08-2022, 05:42 PM

This iN·Command HVAC troubleshooting guide may help.

https://asasupportdocs.blob.core.win...3%20NCSP35.pdf

ChuckS · 01-09-2022, 05:30 AM

Quote:

Originally Posted by Shelton

Dip switches are set right, double checked them. I’m thinking my gateway box is bad and causing my issue because now it is throwing 1, 2, and 8 error codes. Zone 2 is now working fine after update. So the box I moved the problem followed the box.

If I have read your findings correctly.. its early here and on my first cup of java... the problem followed the box... then the box it bad

The errors you are listing are all CANBUS as previously stated...

ChuckS · 01-09-2022, 05:37 AM

And YES .. you could move the resistor from the New Zone 3 to Zone 2... And you would have to disconnect the CANBUS line from Zone 2 that runs to Zone 3 OTHERWISE even when you reset the CANBUS by cycling power the system may still see that third zone with the CANBUS line connected to it...

if you do this then of course Zone 3 will be completely dead to the system and not function but zones 1 and 2 should now work properly till you get replacement part..

ChuckS · 01-09-2022, 05:41 AM

Quote:

Originally Posted by M&M2

This iN·Command HVAC troubleshooting guide may help.

https://asasupportdocs.blob.core.win...3%20NCSP35.pdf

The link is a good one EXCEPT ASA Jensen for got to include the FURNACE when they made this PDF.. the Furnace is controlled by Zone 1 with two blue signal wires that run from Zone control board on the A/C unit down to the furnace control board

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