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RV Tech Q&A: January 2019

Originally Published in Trailer Life Magazine

Refrigerator Electric Operation

Red letter QTo save on electricity, I plugged the refrigerator directly into a garage outlet. Now the refrigerator doesn’t work on electricity. It still seems to work OK on the gas mode. Did I blow a fuse or something worse?

I have seen other fifth-wheels doing this. I try to bypass using the converter all the time.

Thomas Gerlach | Ramsey, Minnesota

Green letter A

Well, there are a couple of possibilities, Thomas. First of all, your RV refrigerator requires 12-volts DC and 120-volts AC power at all times to run on AC. Plugging the refrigerator into the garage receptacle and disconnecting the house battery (by switch or manually) will make it impossible for the refrigerator to operate, as the circuit boards require the DC power source. It’s best to plug the RV in via the power cord. This way the converter/charger provides the DC current, and the shorepower provides the AC. The batteries get charged at the same time, which is a bonus. Just be sure to keep the water up in the batteries.

If the fridge fails to work on AC when plugged into the RV, and you’re sure there’s good power (AC and DC) to the refrigerator, then you may be looking at a burned-out heating element or blown circuit board, which will require a visit by a certified service technician.

Trailer-Axle Jacking

Red letter QI have a 2015 Excel Winslow 31IKE fifth-wheel trailer. Its camping weight is 14,900 pounds, with hitch weight of 2,000 pounds. I know manufacturers recommend jacking the unit by the frame, not the axle. I think if I place a bottle jack under the axle, so the lift point is where the leaf springs are bolted to the axle, I would be jacking at the strongest part of the axle. When I purchased the fifth-wheel from Peterson Industries, the rep stated that I could lift the unit by the four hydraulic leveling jacks. Lippert said no to this, but I have seen it done at the service center.

Kenneth Phibbs | Powhatan, Virginia

Green letter A

There seems to be some disagreement in the industry about this, Kenneth, so we reached out to Kelly Ross, technical training manager for Lippert Components. “We don’t recommend lifting the unit at any part of the axle. We always recommend following the manufacturer’s instructions on this subject,” Ross says. The reason for this is that most trailer axles are round, hollow tubes, rated for only a portion of the trailer’s weight. Jacking the trailer up via an axle concentrates all the weight on one spot of one axle, which can result in a bent axle.

With regard to using the leveling system to lift the unit off the ground, Ross adds, “We do not recommend lifting the unit with the leveling jacks. If this occurs during [the] leveling process, we would recommend that the coach be moved to keep the unit stable for a better camping experience.”

The frame is the safest place to lift the trailer. Don’t forget to use jack stands or stacks of wood blocking underneath the frame as safety backups to the main jack.

Black-Water Valve Leak

Red letter QI have a 2017 Jayco hybrid trailer. On our last trip, there was an accumulation of black water sitting behind the waste-pipe cap. There was so much that I needed to use a bucket to catch the not-so-nice water. I checked to make sure that the slide valve was securely closed before we moved to our next location. After arriving and setting up, I brought the bucket over to catch any black water, and once again there was more than a quart sitting behind the cap.

I took the trailer to the local dealership to have it checked. The technician called and told me there may be a $70 charge for the inspection, if it is not a faulty mechanism. He also explained that, with the trailer not being level, black water can get through the slide valve. My response was, “Say what?! You’re telling me that black water can get by the slide valve just because a trailer is not level?” I thought the purpose of the slide valve was to keep all the gray and black water behind it, and the section of pipe to the cap should be dry. Please elaborate.

Kevin Kobus| Prescott Valley, Arizona

Green letter A

It appears that the “technician” was terribly misinformed. With the black-water slide valve (also known as a blade valve) closed, there should be almost no fluid between the valve and the pipe cap. I say “almost” because if there’s a long run (pipe) between the tank and valve, it’s possible for a little wastewater to become trapped if the trailer is not level and not allowed to drain completely. But it shouldn’t be enough to require being caught in a bucket. A slide-valve seal can wear out with age, but given that the one in your RV is leaking that badly, and it’s only a couple of years old, tells me it could be defective, or it may have something stuck in the seal channel that’s preventing it from closing completely.

Tow-Dolly Brakes

Red letter QI tow a car on a dolly with my motorhome from Canada to Florida and back every year. There’s a problem that occurs often but not always. When I apply the brakes at low speed, less than 20 mph, the tow dolly’s brakes rapidly lock and unlock, causing the car and dolly to hammer against the tow ball in an alarming manner. I have replaced the master cylinder, the internal shock absorber, the wheel cylinders and the brake shoes. The dolly is mounted the recommended 19 inches above the ground on the ball.

Do you have any idea what might be causing this situation? I am even thinking of changing from surge brakes to electric brakes to stop this heart-attack-inducing pounding!

George Lyche | Kingston, Ontario

Green letter A

A couple of possible causes include improperly bled brake lines and a slight mismatch of the new parts. Air in the brake lines can cause intermittent brake performance, and the master cylinder also needs to be bled. There is a flow orifice in the cylinder, and the old one may have been smaller, so have that checked as well. There are also sliding pads on the sides of the mechanism that can wear out and allow too much lateral hitch-mount movement, and that can also cause erratic brake action. Switching to electric brakes with a brake control inside the motorhome is also a viable solution.


One thing your answer to August 2018’s “Double Towing” did not cover was that some states require a double endorsement on your driver’s license when towing two trailers. It’s not usually a problem until there is an accident; then you would legally be an unqualified driver at that point.

Larry Brown | Holland, Michigan

Thank you for the addendum, Larry. That’s the kind of information people should look for when they do their research about towing two trailers, such as a boat behind a fifth-wheel. Lacking any federal standards for this, each state has its own requirements for towing an additional trailer. This is definitely one situation where it’s best to be thorough when doing one’s homework.

See Related Story:
RV Clinic FAQ:
Top 20 Tech Questions

Have a Question?

Email or write to RV Clinic, 2750 Park View Court, Suite 240, Oxnard, California 93036. Include your full name and hometown. Selected letters will be answered in the magazine, but time does not permit individual replies. No phone calls, please.

Man with grey beard and wearing blue shirt leaning over open car hoodJeff Johnston served as technical director of Trailer Life for 20 years and has been an RV enthusiast, mechanic and writer since he could hold a wrench. In his monthly RV Clinic column, Jeff replies to Trailer Life readers’ technical questions about RVs and tow vehicles. He also serves as associate producer of Rollin’ On TV, a nationally syndicated television program for RV enthusiasts.

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