Tech Q&A: September 2020

Electricity symbol for Trailer Life RV Clinic Tech Q&A column

48-Volt Truck Power?

Red letter QYears back there was a lot written about the conversion from 12 volts DC to 48 volts for light trucks, RVs and cars. Somehow, all that faded away, and no change was made. Twelve-volt DC systems are still the mainstay of the industry. I don’t remember ever reading about the decision to drop the conversion project.

One of the benefits of the change would have been the use of thinner wire in an era of ever-increasing demand for more and more wire in newer vehicles. A higher number gauge wire (thinner and lighter) would carry the reduced amperage needed. There must have been some overriding disadvantage to cause the project to be scrapped. What happened?
Hank Snell | Eugene, Oregon

Green letter AAuto manufacturers are always looking ahead to the next possible big thing in technology, and some of those speculations are just that — educated guesses or predictions. There may have been some talk about using 48-volt DC systems in light trucks, and there were probably some engineering tests done, but common sense prevailed, and the plans were shelved at some point.

It’s probable that the engineering plans presented didn’t pencil out to lower vehicle costs, less warranty work, and more sales and profit per unit, which are the driving forces for an auto manufacturer bean counter. At some point someone might have also given a passing thought to the inconvenience to the buyer, who now had to deal with an entirely new set of electrical system needs, plus all the electrical aftermarket accessory builders, including RV trailer manufacturers and their suppliers needing to retool for 48-volt power for some vehicles and 12-volt for others, but end-user convenience is seldom high on a priority list for manufacturers. Just as well that the 48-volt idea died on the vine.

Trailer Tire Change

Red letter QWe have a 2016 Keystone Cougar 326RDS fifth-wheel. This will be our third season with it, and we absolutely love it. We just had it out and had our first flat tire. Thankfully, we were able to use some wood that we had, plus the rear leveling jacks, to get it high enough to be able to replace the tire. Not sure if that’s the best way to do it, but it worked.

My question is, is there an easier, safer and/or quicker way to change a tire on our dual-axle fifth-wheel?
Tim Etner | York, Pennsylvania

Green letter AThe best way we recommend for changing a trailer’s flat tire is to follow the instructions in your owner’s manual, Tim. Generally, hydraulic leveling jacks should not be used for lifting the RV for climbing underneath without solid shoring. Stabilizing jacks should never be used for trailer weight bearing, period.

As a rule, RV and axle manuals suggest you jack the trailer by lifting its frame rather than the axle. This means you’ll be lifting the frame extra high because the suspension on that axle end needs to “droop” and bottom out before it starts lifting the tire from the ground. Then you need to lift it higher still, due to the bad tire being flat on the bottom, to clear the ground enough to install the fully inflated spare.

All that extra-high frame lifting seems counterintuitive to a safe tire-changing process, as opposed to just jacking up the axle end and being done with it, but that’s what the RV manufacturers want, so that’s the story we need to stick with. It basically has to do with the fact that most trailer axles are hollow tubes that are not designed to support the weight of the trailer on one axle and on one small point on one side of the axle. Often this bends the axle, leading to alignment problems or worse, requiring replacement of the axle.

You can help yourself out with this process a couple of ways. You can roll the trailer’s good tire on that side up on a stack of wood blocks to help lift the entire chassis, and that reduces the distance you need to raise the frame. Or you can use one of the commercially available products designed to safely roll the tire up on a curved wedge for lifting purposes. These include the Andersen Hitches Rapid Jack and the Camco Trailer-Aid Plus.

As for an easier, safer and/or quicker solution, join a roadside assistance program like the ones Good Sam and AAA offer. That’s about the only way to make it happen easier and safer, and possibly quicker. Just make sure they don’t jack up the trailer by the axle.

Ice-Maker Conundrum

Red letter QOur fifth-wheel, a 2019 Forest River Cedar Creek Hathaway 34IK, has been everything we ever dreamed of, but we could use a little technical help regarding the Insignia four-door residential fridge’s ice maker. The fridge normally runs off an inverter when we’re not plugged in. We camped five times in 2019, and we do not seem to know how to consistently be able to make ice.

We did manage to find the shutoff valve located outside the unit by the left two wheels. Once we opened that, we got ice on our first trip out. Since that trip, we have managed to get ice only 50 percent of the time. One time, much to our surprise, it made ice while we were heading back home. We have had full-service sites and used the pressurized water, and other times relied only on the freshwater tank.

Twice we called the dealer where we purchased it and didn’t got a call back. We researched the manuals and have done exactly what it says, but still no ice half the time. I have a gut feeling that the ice maker works only when using water from the freshwater tank, but I have no proof of that. Logically, the fifth-wheel should be plumbed from the factory to make ice using either pressurized water or the freshwater tank. We even called a service number we found online for Insignia, but the person on the line was from halfway around the world and had no idea what an icemaker even was.
Dale Kissell | Springfield, Ohio

Green letter AYour refrigerator’s ice maker needs a pressurized water supply to operate. This water can come from being hooked up to a city-water source, which pressurizes the entire RV’s plumbing system, or the fifth-wheel’s water pump drawing from the freshwater tank when your RV is not connected to city water. If there’s no pressurized water available, the ice maker won’t work because it can’t draw the water in by itself.

As you’ve discovered from your owner’s manual research, many RVs have a series of T-handle water valves, generally grouped in a service compartment, that allow you to route the plumbing-system water as needed. When you hook the freshwater hose to city water, one valve, for example, may route that water toward filling the fresh tank, or you change the valve, and now it’s pressurizing the plumbing for city-water use. Other valves, for example, cause the water pump to draw from the fresh tank for general system use, or draw from a separate winterizing hose. Not all RV manufacturers are completely diligent about clearly labeling these valves, so it may call for some repeat owner’s manual study to figure them out.

As for the time you had some mystery ice appear while traveling back home, it’s possible you had the water pump switched on. If you normally turn off the 12-volt DC pump when traveling, you would not have any ice production, even if the fridge is still operating via the inverter. In some RVs, with the water inlet valve turned to “Run on city water” instead of filling the fresh tank, the pump would run if switched on, but nothing is being pumped. That could also be a source for the erratic ice making.

As for your do-nothing, no-return-calls dealer, you’ll probably need to make an in-person visit to get any traction on that. Go to the dealer first without the trailer to see if they can talk you through it. If the trailer needs to go in, make a service appointment right there and then. Have one of their technicians go over the plumbing to inspect its functions and explain how to ensure the ice maker works all of the time. Another option would be to call the factory for assistance. The Cedar Creek Hathaway Edition has its own customer and technical service number: (260) 593-4000.

Downsizing Tow Rig

Red letter QWe bought our 2005 Dodge Ram 2500 diesel (Crew Cab) to tow our 12,000-pound fifth-wheel trailer 15 years ago. We are on our third fifth-wheel now, and its weight is just over 7,000 pounds, so we are thinking of downsizing the truck to a 1500 model. We are looking at a 2016 Ram 1500 Laramie with a 5.7-liter Hemi and a 2016 Ford F-150 Lariat with a 5.0-liter V-8. We are leaning toward the Ford, but it’s significantly more expensive ($7,000) than the Dodge. Can you give us your thoughts to help us make a decision?
David Bell | Johnstown, Ontario

Green letter AFirst of all, I’m almost entirely brand-agnostic when it comes to buying a truck. I look for features that will do the job I want, regardless of who built the truck. That said, the only detail that might deter choosing a Ram would be the truck’s coil-spring rear suspension. I don’t believe there are any types of off-the-shelf airbags or other suspension aids that can be used on the Ram 1500, or they’d need to be a custom installation if needed.

The best setup is when you choose a tow rig that can handle the wet-and-loaded trailer weight plus the hitch weight and the added weight of any cargo and  passengers without exceeding the truck’s tow rating, its gvwr or rear gawr.

Even with that kind of proper tow-rig setup, the truck can squat more than you’d like in the back, but that’s what happens with a good-size load in a tow rig. In that situation you may want to consider a suspension aid of some kind, such as airbags, SumoSprings or some type of add-a-leaf type of overload springs. You should not need to depend on these add-ons to carry the designated load but they can help the truck and trailer handle better and ride in a more-level configuration.

And since you said the trailer is “just over 7,000 pounds” it sounds as if that’s an estimate. You’d do well to haul the trailer to a certified public scale and weigh it, loaded and ready for the road, so you know specifically which numbers you’re working with.


Have a Tech Question?

Email [email protected] and include your full name and hometown. Selected letters will be answered in the monthly RV Clinic column, but time does not permit individual replies.


Man leaning over engine wearing blue shirtJeff 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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