You Have Questions, WFCO Has Answers

For 40 years, WFCO has provided innovative “answers” to challenges faced by manufacturers, dealerships, and RV service centers. These answers’ quality, reliability, and affordability 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. Designed to answer questions for RV owners, technicians, and manufacturers, it is divided into three sections under General, Electrical, and Troubleshooting headings. The latter can benefit technicians with step-by-step directions 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 length, the heavier the gage of wire required. Many charts on the internet 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. You see the voltage the monitoring circuit needs that turns the red LED ON when a fuse is blown.

Should my fan run all the time?

No. The load controls the fan. The fan will start running at a low speed when you have approx. 3.0 to 6.0 dc amp draw. It will increase speed as you add more load until you have approx. 14.0 to 15.0 amps draw. The fan is at maximum speed and will stay there even if you add more load. The fan will shut off if the amperage drops below 3.0 to 6.0 dc amps.

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 indicates a blown fuse. If the output circuit has no load (turning off the switch or turning off the appliance), the red LED will not light even if the fuse is blown 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 12 V 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 V dc.
  5. Check your battery. It might be damaged, or the water level may be low.

Remember that your battery can pull up to 30 A or more from the converter. Low temperatures also will have a significant effect on your battery’s performance.

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

For any WFCO resources, tools, and information on our products, email with your request, or click here to download the WFCO Training Catalog. To learn more about our products through video, click here.