WFCO Power Converter: “No DC output / reverse polarity”
warning RV power converter problems
What it means
If a WF-8900-AD power center produces no 12 V output, WFCO's procedure points first to the reverse-polarity fuses on the fuse board, which double as the main link between the converter section and the DC bus and blow if the battery is ever connected backwards. Separately, a continuous audible alarm in the power center signals that incoming AC line and neutral are reversed.
Most likely causes
- Battery connected in reverse polarity, blowing the reverse-polarity fuses and cutting all converter DC output most likely
- No incoming 120 VAC (unplugged, tripped breaker, generator off) common
- Open inline fuse or loose connection in the battery wiring common
- Incoming AC line/neutral wired backwards (triggers the audible AC reverse-polarity alarm, not a DC fault) less common
- Failed Main Board Assembly (converter section) rare
Safe checks you can do yourself
- Confirm the RV is on a live 105-130 VAC source and the main breaker is on.
- To test output, disconnect the battery cables at the battery and measure across them; 13.6-14.6 V means the converter is working.
- If output is 0 V, remove and inspect the reverse-polarity fuses on the fuse board (visual, then continuity test).
- Check for an RV-installed inline fuse in the battery wire and for loose connections.
- If a steady alarm sounds, suspect reversed AC line/neutral at the pedestal or wiring; do not ignore it.
How to reset / clear No DC output / reverse polarity
- Disconnect AC and the battery before replacing fuses.
- Correct any reverse battery wiring, then install reverse-polarity fuses of the same size and rating.
- For the AC alarm, correct the incoming line/neutral connection; the alarm stops once AC polarity is right.
When to call a technician
Reverse-polarity fuses are intact and AC is present but output still reads 0.0 V (the Main Board Assembly may be defective), fuses blow repeatedly, or the AC reverse-polarity alarm persists after checking the connection.
Applies to
WF-8935-AD · WF-8945-AD · WF-8955-AD · WF-8965-AD · WF-8975-AD
FAQ
What does WFCO Power Converter code "No DC output / reverse polarity" mean?
If a WF-8900-AD power center produces no 12 V output, WFCO's procedure points first to the reverse-polarity fuses on the fuse board, which double as the main link between the converter section and the DC bus and blow if the battery is ever connected backwards. Separately, a continuous audible alarm in the power center signals that incoming AC line and neutral are reversed.
How do I reset WFCO Power Converter No DC output / reverse polarity?
Disconnect AC and the battery before replacing fuses. Correct any reverse battery wiring, then install reverse-polarity fuses of the same size and rating. For the AC alarm, correct the incoming line/neutral connection; the alarm stops once AC polarity is right.
What is the most common cause of No DC output / reverse polarity on a WFCO Power Converter?
The most likely cause is battery connected in reverse polarity, blowing the reverse-polarity fuses and cutting all converter dc output.
Related · WFCO power converter
On a WF-8900-AD Auto-Detect power center, an integrated LED … DC fuse red LED (blown fuse)
Each of the eleven DC fuse positions on the WF-8900 fuse boa…
Sources
- Operator's Manual WF-8900-AD Series Power Center — Checking Converter Output Voltage; Reverse Polarity Fuses; AC Reverse Polarity audible alarm; Troubleshooting Flow Chart (WFCO / Arterra Distribution)
Note: Reverse-polarity fuse count/rating varies by model (e.g., WF-8935-AD one 40 A; WF-8945-AD two 30 A; WF-8975-AD four 20 A). The expected good-output reading is 13.6 VDC +/-0.2 measured across the negative lug and VCC lug on the fuse board, or 13.6-14.6 V at the battery depending on charge stage.
● Last verified 2026-06-29 · compiled from manufacturer documentation. Codes can vary by model year — always cross-check your unit’s manual.