Light and Dark
Dear RV Doctor:
I have an issue with the lighting in my 1982 motorhome. Several interior lights (in the hallway and two in the bedroom) sometimes work but other times do not. How do I figure out what is causing this to happen?
Pat Ogilvie
Jacksonville, Florida
Troubleshooting intermittent 12-volt-DC electrical issues is one of the most difficult tasks to learn, even for professional RV service technicians. I teach my students to mentally break down the complete battery system into sections and troubleshoot from largest to smallest. In most instances, when components function part of the time but not other times, it is safe to rule out the actual device as the culprit. In other words, when a lamp sometimes works, there’s probably nothing wrong with the lamp itself. If a short circuit has occurred somewhere, fuses would blow and the lamp would cease to turn on at all. This allows us to rule out a direct short on the positive side of the circuit.
Experience has shown that in most cases of intermittent operation, the problem is likely a faulty connection somewhere in the system. You’ve already narrowed the problem to that lamp circuit, but DC electrical connections occur on both the positive and negative sides of the system. The starting point would be the connections at the battery itself. Be sure all connections are clean, dry, and tight, beginning at the battery terminals. At every point where a wire or cable terminates or physically connects to another wire or terminal, there is the potential for a problem. Loose connections, clamps, terminals, fuses, plugs, etc., at any point within that lamp circuit on the positive side, or anywhere within the negative side of the complete DC system, could be the cause of your problem.
I’d focus on the negative side first. Be sure to check the main grounding connection on the frame of the RV. Follow the negative cable from the battery bank and ensure that the connection to the frame is clean, dry, and tight. A motorhome as old as yours has likely seen some miles, and all those years of bouncing along down the highway may have loosened up some connections. Also, as a motorhome ages, corrosion develops at those connecting points. A loose or corroded connection is the number one cause of intermittent operation of any 12-volt-DC component. It’s a matter of isolating the fault (again, thinking from large to small) by checking each connection from point A to point B.
If the cables or wires seemingly disappear into the floor or ceiling, it may be easier to run a new conductor from the fuse block to the lamps, assuming all connections between the fuse block back to the battery bank, and ultimately to the frame, are secure and proper. I urge technicians to spend about an hour testing and measuring. If they can’t locate the fault and rectify it within an hour or so, simply route a new conductor. Keep in mind, the fault could be on either the positive or the negative wires to those lamps. This may or may not be within the scope of your ability, so use your own judgment; it may be necessary to seek professional help.
Bent and Damaged
Dear RV Doctor:
I purchased a preowned 2008 RV and recently the furnace exhaust and intake cover was damaged. I need to remove the damaged cover only and replace it with a new one. I took off the six screws, but the cover would not come off. I was afraid to force it, as it might cause damage to the heater itself. It appears that there are two rivets also holding the cover on, but I do not know how to get them loose without damaging the furnace. Any help would be appreciated.
David Berkebile
Friedens, Pennsylvania
If the Suburban vent is attached to a larger aluminum cover containing four additional screws, it might be necessary to remove that larger panel at the same time. The chrome intake/exhaust vent portion contains tubes that slide into the actual furnace inside the coach. When you pull the vent with that larger panel, it will have to come straight out from the side of the coach to enable the tubes to slide out of their matching tubes on the furnace. Those rivets you see simply connect the tube extensions to the exterior vent assembly, so you do not have to drill them out or remove them. But if all you see is the chrome vent assembly on the side of the coach (no panel), remove the six screws and pull straight out laterally and the vent assembly should come off along with those short tubes. Oftentimes, the sealant used may act as a “glue” of sorts, making it difficult to remove the assembly. Some Suburban vent assemblies do not have the additional larger panel. I hope this helps!
Leaking and Wondering
Dear RV Doctor:
After we were on the road for about two days, water began leaking into a compartment on the passenger side of the motorhome. It appears to be gray water. It is a lot of water and nearly filled the bottom of the compartment to the point that I had to drill a hole to drain the water. I believe the compartment is located across from the holding tanks. What do you think is happening? I had to have the coach winched off a pole a few months ago by a tow truck. They had to drag it about 4 feet sideways to get it cleared from the pole. Could that have pulled something apart?
Paul Martin
Knoxville, Tennessee
It’s entirely possible that a connection pulled loose when the motorhome was cranked off that pole, but it would take a closer inspection to be sure. By code, all holding tanks are required to be removable, so there has to be a way to access the fittings, valves, etc. It seems strange that it took a couple days for the leak to become evident. A cracked tank might explain that, but, again, I think it’s going to be necessary to start taking things apart to expose the gray-water tank. It’s tough to diagnose without actually seeing the situation. I hope the repair is something simple. I’m not going to ask how your motorhome managed to be stuck to that pole in the first place.
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