Desperate help needed A/C Furnace

REDRASCLE · 10-06-2023, 03:14 PM

I really need some help fellow rv’ers!
We went on vacation and I forgot to unplug my cougar trailer, and when we got back my batteries on the rv as well a my truck battery was completely dead. Since then I replaced both rv batteries and the converter. But now my AC/furnace are not working. The in-command system shows a temp for the setting but a -F for the thermistor. I have tried everything including the things that others have posted, including unplugging the shore power, turn ff the batteries for about 30 seconds, turning them back on then plugging in the shore power, and still no changes.
Any help would be appreciated, winter is coming so I really need to get this working. Thanks!

LHaven · 10-06-2023, 04:20 PM

When I see a report of- F, my thoughts immediately go to the known problem where some models came out of the factory with no terminators on their HVAC bus. Installing the proper terminator fixes that issue, if that's your issue. I can't see a hard connection between this problem and your having killed your battery, but the terminator thing is highly nondeterministic, and shows up or doesn't as it feels like it.

**JRTJH** · 10-06-2023, 06:16 PM

Quote:

Originally Posted by REDRASCLE

I really need some help fellow rv’ers!
We went on vacation and I forgot to unplug my cougar trailer, and when we got back my batteries on the rv as well a my truck battery was completely dead. Since then I replaced both rv batteries and the converter. But now my AC/furnace are not working. The in-command system shows a temp for the setting but a -F for the thermistor. I have tried everything including the things that others have posted, including unplugging the shore power, turn ff the batteries for about 30 seconds, turning them back on then plugging in the shore power, and still no changes.
Any help would be appreciated, winter is coming so I really need to get this working. Thanks!

First, if you forgot to unplug the trailer and when you got back the batteries and converter were "completely dead", I would suspect that the trailer either had a high voltage surge, an extended brown out condition (low voltage that damaged the trailer systems) or was struck by lightening or a battery that failed and then damaged the other components in turn...

Normally, with the trailer plugged into shore power, the converter will keep the batteries charged and unless there is a battery problem, there should not be any battery damage from leaving it connected with batteries connected and charging.

The air conditioner fan running constantly also leads to the suspicion that there was a shore power surge/issue/lightening strike that affected the A/C fan motor system.

When it comes to "rebooting your system", if you disconnected shore power and "turned the batteries off", your electrical system may still be sending 12 volt power from the batteries to the InCommand system. Why? Many wiring systems do not completely remove power from the "safety features" and the InCommand system and its "global connect remote features",(so they remain functional and powered on, even when the battery switch is turned off.

The best way to assure a "complete reboot" is to disconnect the ground cable on the battery, turn the battery switch off and remove shore power by unplugging the trailer from the power source and if you have a solar system, completely disable it as well. Wait about 5 minutes (30 seconds may not be long enough in some systems, depending on what else is draining the residual power in the system while the InCommand "drains itself down to reset all the logic circuits"...

So, try a complete reboot with ALL power removed, then start looking for evidence of a power surge or brown-out condition....

HOPEFULLY, you do have an EMS ????? If not, you may have suffered significant damage and it may be time to contact an RV repairman and possibly your insurance company.

LHaven · 10-06-2023, 06:57 PM

I read it as he "forgot to unplug" his trailer from his truck, and vampire loads killed both batteries. OP needs to clarify if shore power was involved.

ChuckS · 10-07-2023, 03:36 AM

Anytime the In Command HVAC display shows - - F this means the Gateways and control boxes are not getting 12 vdc and therfore can't read the remote temp sensors..

Since the OPs HVAC worked before this issue he obviously had an EOL resistor in place or the system would never have worked right

** Without the EOL in place the CANBUS cant determine where the ENd of Line actually is in the CANBUS string.

HARD REBOOT to let the relays in the gateways have a chance to reset as previously stated...

It also makes a difference as to what AC model you have...
Dometic uses gateways and control boxes
Coleman uses their Netzone gateway to control the AC control box

ChuckS · 10-07-2023, 03:44 AM

If you read this KSB it should help you understand your issues with the In Command HVAC displaying no temp from the remote sensors..

This KSB affected ALL Cougar models and other models ( year groups )

REDRASCLE · 10-07-2023, 10:23 AM

I tried the total reboot and there’s no difference. The shore power did have a brownout, but I had a surge protector hooked up to it.
Also the A/C is a dometic

REDRASCLE · 10-07-2023, 10:25 AM

Sorry I left out this info

LHaven · 10-07-2023, 03:21 PM

Unfortunately, a plain surge protector typically isn't going to protect you from brownouts. EMS (electrical management system) units will safely cut power to your rig if the shore power gets hinky in any way. They cost 2-3x what surges cost, but it's insurance. (Apologies if your "surge protector" is really an EMS, as some manufacturers title their EMS products confusingly, e.g., Progressive's "EMS-PT30X Portable RV Surge Protector.")

Also, it would help if you would visit User CP and create a "signature" containing your trailer and truck year and model, as you see below, so people can answer your questions more easily. Thanks.

dwdlt · 10-12-2023, 09:32 AM

Not sure if this will help or not, but I had a similar situation on my cougar 5th wheel. My fix was a circuit breaker. Not a plug in fuse, but a circuit breaker. If you haven't already checked that, I would recommend it.

Also, what model and year of Cougar do you have, and does it have the solar 200 system on it?

tallen · 10-12-2023, 10:05 AM

Quote:

Originally Posted by dwdlt

Not sure if this will help or not, but I had a similar situation on my cougar 5th wheel. My fix was a circuit breaker. Not a plug in fuse, but a circuit breaker. If you haven't already checked that, I would recommend it.

Also, what model and year of Cougar do you have, and does it have the solar 200 system on it?

OP gave Trailer is a 2020 cougar 29FKD in post #8

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