"I have gone through two deckmount converter-chargers in 5 days. It seems that rough roads lead to the converter-charger failing. The interior 12 volt circuits seem to also be offline. I am beginning to believe I have a problem with the main power panel or the wiring of it. Even with a fully charged battery I have no interior lights. However, the slides still work, the auto-level system still works, and the refrigerator still works. Everything on the 110 volt AC side still seems to work. The converter-charger that was replaced was a WF-9855. It was replaced with a WF-9855-AD. Everything worked fine after the replacement. We towed the 5th wheel about 500 miles and somewhere along the way the unit failed and when we plugged in at our destination the converter-charger was no longer putting out 12 volts."
I hope you saved the old WFCO unit. It may be OK.
Slides and leveling are often connected to the battery independent of other house 12 volt appliances. This indicates the problem is with the other stuff wiring.
Possible:
Battery to fuse panel line usually has a circuit breaker in the line. It may be self resetting. That circuit breaker may be defective, or simply need resetting. Mine is mounted on the tongue. Some are just underneath the bottom front.
There is often a junction box just under the bottom front. Cables can become disconnected there.
The WFCO usually has access to 120v circuit breakers, 12v fuses and heavy cable screw connections inside a panel door. Those screw connections have loosened on mine more than once.
Fuses on the WFCO panel may have blown. There are usually "reverse polarity fuses" and another main fuse that can disconnect most 12 v circuits. Check those fuses. Sometimes the fuses look good but don't work, so good to test them.
There is a test procedure for the WFCO converter/chargers. See the WFCO Owner's manual for the test on the old and new units.
