You Have Questions, WFCO Has Answers

For 40 years WFCO has provided innovative “answers” to challenges faced by manufacturers, dealerships, and RV service centers. The quality, reliability and affordability of these answers have put WFCO products in four out of five RVs made today.

Besides providing a quick answer to your questions, WFCO’s FAQ section is a great place to educate yourself about WFCO products and power products in general. Designed to answer questions for RV owners, technicians, and manufacturers, it is divided into three sections under the headings of General, Electrical, and Troubleshooting. The latter can be particularly helpful for technicians with step-by-step directions offered toward a solution. Below are some of our most popular FAQs and their respective answers.

What wire size should I have from my battery to the converter?

Wire size is based on the distance from the battery to the converter panel. The longer the distance, the heavier the gage of wire that is required. There are many charts on the internet that will give you this information.

Why do I have voltage on the DC fuse board output terminals even though the fuse is not in place?

This is normal. There is only voltage present- no amperage. The voltage you are seeing is the voltage needed by the monitoring circuit that turns the red LED ON when a fuse is blown.

Should my fan run all the time?

No. The fan is controlled by the load. The fan will start running at a low speed when you have approx. 3.0 to 6.0 DC Amp draw. It will increase in speed as you add more load until you have approx. 14.0 to 15.0 Amps draw. At this point, the fan is at its maximum speed and will stay there even if you add more load, should amperage drop below 3.0 to 6.0 DC amps, the fan will shut off.

Why can I pull my fuses out of the fuse board and some of the LEDs light up but some do not?

When a fuse blows, the red LED comes ON indicating a blown fuse. If for some reason the output circuit has no load on it (turning off the switch or turning off the appliance), the red LED will not light even if the fuse is blow or removed.

My lights are dimming – what is wrong?

If the lights in the RV are dimming, that usually means that the converter is overloaded or that your coach is running only on batteries.

  1. Remove some of the load by turning off 12V lights and appliances.
  2. Turn off the converter for 10 seconds to allow the unit to discharge by either turning off the breaker or unplugging the unit.
  3. Turn the converter back on.
  4. Check the output voltage of the converter. It should be approximately 13.6 VDC.
  5. Check your battery. It might be damaged or the water level may be low.

Keep in mind that your battery can pull up to 30A or more from the converter. Low temperatures also will have major effect on your battery’s performance.

You can see the full list of FAQs here, or look for “FAQs” under the Support tab on