RV Refrigerator "Auto Mode" Problem

I recently purchased a Coachman Class A motorhome with a Dometic refrigerator Model RM2852 that has an "Auto Mode" switch to start up electrically using 120-volts alternating current. It also has a "Gas Mode" switch to start up by using propane. After several successful trips using both options, a problem has developed where I can only use the "Gas Mode" switch to start the refrigerator. It will not start using the "Auto Mode". The light inside will come on so it is getting power but it will not get cold even after 24 hours. Can you advise what is causing this problem? Patrick H., (Hockessin, DE)

Patrick, you say you can run the refrigerator on “Gas Mode,” but when you switch it to “Auto Mode” does any indicator lamp illuminate on the control panel? When on “Auto” and the coach is energized with 120-volts AC, both the “Auto” and “AC” lamps should light up. If not, there may be a blown fuse on the lower circuit board. It’s relatively easy to check if you have a volt, ohm multimeter. It’s possible you may have a problem with other components or wiring within the AC circuitry, but the most common cause is a blown AC fuse on the lower circuit board. But when it’s running on “Auto Mode,” that indicator lamp should remain lit. 

Here’s what you can do; Unplug the refrigerator from the receptacle and gain access to the lower circuit board at the rear of the refrigerator. Then carefully remove the cover. Once removed, plug the refrigerator back in, power the RV with 120-volts AC and set the refrigerator to the “Auto Mode.” Next measure for AC voltage at terminals J5 and J6 on the board itself. If the unit is already cold, you may have to turn the thermostat to a lower temperature setting or wait until it warms a bit. You should also be able to measure the line voltage on terminals J7 and J8 as they lead directly to the AC heating element. If you don’t have voltage at these terminals, check for continuity of the 5-amp AC fuse and the 3-amp DC fuse on the board. Chances are the 3-amp DC fuse is good since the DC lamp works inside the refrigerator, but I’m guessing the 5-amp AC fuse is blown. A worst-case scenario is that the board itself is faulty. If indeed you can measure line voltage at terminals J7 and J8, then it’s possible you have a burned out heating element. If that is the case, I’d recommend a pro service tech do the replacement.

Also realize that if the serial number of your refrigerator is between 101XXXXX through 152XXXXX, it is subject to a recall notice. Ensure your unit has been retrofitted with the recall kit. 

Must be Approved for RVs

In answering an earlier question about replacing the water heater with an all-electric one, why did you only mention the Atwood and Suburban? Many residential electric hot water heaters are available at a much lower price than the RV models. We recently installed a 19-gallon water heater we bought at Lowe's in our fifth wheel. Dwight N. (Titusville, FL)

Dwight, currently only Atwood and Suburban manufacture standard propane and propane/electric water heaters for the RV market. I can only recommend those products that are approved for use in recreation vehicles. Aftermarket products must be RV-approved in order for the RV to remain code compliant. I can’t imagine the number of emails I’d receive if I ever recommended a non-approved product for use in RVs. The Standard for Recreation Vehicles, the NFPA 1192 is quite clear. Of course, RV owners can choose to install any product they feel inclined to, but from a safety standpoint, especially concerning 120-volts AC and propane gas, I can only recommend or endorse RV-approved products and services.
 

RV Battery Wiring

I have a eight year-old Nash 5th wheeler. I have one completely dead battery in it now. I want to replace it with two, (Group 24), 12-volt batteries. I'm not sure how to hook them up. There is not enough room for two, small 6-volt batteries, as the space is quite small. Can you help me? I love your weekly feature on the RV Travel newsletter every Saturday. S. Stepnowski (no city/state)

Stan, parallel 12-volt batteries are interconnected by routing a battery cable from the positive post of one battery to the other positive post on the other battery. Same for the negative cable; negative to negative. The positive side of the load is then connected to the positive post of one battery and the negative side of the load is connected to the negative post on the other battery. That’s the best scenario for a two-battery bank.

But if you have room for two, 12-volt batteries, you will have room for two, 6-volt batteries wired in series. Typically, two 6-volt batteries wired in series will yield a little more storage capacity than two, 12-volt batteries wired in parallel; assuming the batteries have the same footprint. But it’s certainly your choice!

Thanks for the mention of the RVtravel.com Newsletter. Be sure to sign up for the RV Doctor Newsletter too! (Check the upper right corner of this page, second box down from the top).

Wire Colors Can be Confusing!

What genius decided to use black and white as positive and negative colored wires instead of the automotive red and black? Would it not have been less confusing to everyone to use red and black? S., (Slab City, CA)

Seann, perhaps you're being just too logical! I once had to troubleshoot a wiring issue under the dash of a motorhome. When I crawled under there, every single conductor was yellow! Just like in the converter pictured here, it basically boils down to what the policy is at that factory and what the parts manager at the factory purchases. Most modern coaches will have some type of color code that, at least, makes some sense, especially for the battery charge conductors. The pro techs in the shop are taught to measure everything with a meter anyway. Professional technicians should rarely trust or rely on color for the most part; especially when troubleshooting. Who knows what may have been modified or replaced beforehand! But I hear ya! At least black and white correlates to the AC wiring (black-hot, white-neutral) across the board. 

Problematic Imported RV Tires

We have a Keystone Laredo which came with Mission tires. Within three days we had two tires fail. One had a bubble and the other blew out five miles from home while heading to the mountains. It did damage the trailer. Tireco, (the parent company), will not cover the damage. They say the tire that blew had impact/road hazard damage. I don't believe this at all. We had 50% of the tires go bad on this RV in three days. They did pay for the bubbled tire. I see on the web that there are numerous complaints regarding these tires. Can you, or any reader give me information on these tires, or what recourse we have? Louise C., (Kernersville, NC)

Sorry to hear about your problems with the Mission tires Louise; you evidently are not alone. Check the size of your tires and see if they are on the formal Recall notice. There have been many reported problems with these imported tires; the blogs of full of comments regarding them. Here’s an article that was posted back in 2007 that you might find interesting.

According to some, it simply is not worth the risk to continue using a Mission tire. Most have simply switched to one of the better made US tires and have not looked back. I’ve not heard many positive comments regarding Tireco as well.

I wish I had better news for you, but from a safety perspective, it would be wise to simply replace all the Mission tires with a US-made tire. From my research, it is much better to be safe and absorb the cost than to risk damage or injury. If possible, save and store the old tires in case an opportunity for a rebate or refund becomes a reality.  

Also, understand how vital it is to know the true weight each tire is actually carrying! Individual weight measurements taken at each tire position, using a certified scale, is the only, I repeat, the only way to know how much to inflate each tire. It's also the only way to know if an axle is overloaded to one side. The most common cause of tire failure in the RV industry is a combination of under-inflation and overloading. You must weigh it to know it! Regardless of the brand of tire.

I strongly suggest RVers everywhere contact the Recreation Vehicle Safety and Education Foundation (RVSEF) to inquire about their coach weighing schedule and other weight and safety educational products. RVSEF is the only independent facility fully endorsed by RVIA and RVDA. Visit them at: www.rvsafety.com.

 

5th Wheel Travel Trailers, Inverters and Generators

Do fifth-wheel travel trailers have inverters? If they do not, then I need one with a generator, right? Robert P. (Avon, IN) 

Robert, many 5th wheel travel trailers are indeed equipped with an inverter. In some cases, however, they may not power all 120-volt AC loads in the same manner as an on-board generator. Some trailers are equipped with both an inverter AND a generator. It just depends on that manufacturer. No hard and fast rule here...

Some inverters are not designed to handle some loads like a rooftop air conditioner for instance. My recommendation is to find the trailer you like, see how it is equipped and then upgrade as necessary depending on your planned use of the RV. Just about anything can be done in the aftermarket to upgrade just about any RV according to the owner's wishes! That's what's great about our aftermarket! 

Just so you know, if you're going to purchase an aftermarket inverter, I always recommend investing in a true sine wave output inverter. Modified square wave inverters are more limiting than true sine wave inverters. You'll pay more up front, but with the technology today, the true sine wave output is just as smooth a waveform as electricity from the grid. 

Likewise, some fivers are equipped with a generator. Of course, if you opt for a gasoline unit (vice propane), it will require extra space for a fuel tank too. You'll find AC generators on the larger units, but again, just about anything is possible in the aftermarket! Then again, it's not uncommon to find RVs sold without an inverter OR a generator. You want AC electricity? You'll have to plug into a shoreline source. Choose wisely, but remember, the aftermarket is a wonderful place!