House Calls with the RV Doctor
By Gary Bunzer
DEAR RV DOCTOR:
My emergency start switch is not working on my Fleetwood motorhome. Can you provide troubleshooting steps?
Ron Berube, Endicott, New York
Ron, in many cases, the emergency start switch on a motorhome is nothing more than a momentary dash switch wired to a simple solenoid. On that solenoid you’ll find two large lugs. Each battery system on the motorhome is connected directly to these lugs with a large battery cable. The auxiliary battery’s positive cable connects to one side; the engine battery’s positive cable connects to the other. The solenoid will also have one or two smaller terminals. If yours has one small terminal, this terminal is wired to the dash switch, and the casing of the solenoid must be grounded to the frame of the motorhome by using one of the two mounting bracket holes. If yours has two small terminals, one is ground, and the other goes to the dash switch. With DC power, it really doesn’t matter which of the two smaller terminals is which. When activated, the solenoid closes and sends auxiliary battery voltage through the solenoid to the engine battery cable, thereby connecting both battery systems into one big battery and hopefully providing enough voltage to crank the engine.
To bench test an emergency start solenoid, you’ll need a volt-ohmmeter (VOM) and a battery source. Connect the VOM leads to the two large lugs with the meter set to the Ohm’s scale or the continuity scale. The meter should show infinity. Next, apply positive 12 volts DC to one of the smaller terminals on the solenoid and negative 12 volts (ground) to the other. If the solenoid only has a single small terminal, attach the ground wire of the 12-volt source to the mounting bracket. When voltage is applied, you should hear an audible click as the internal magnet closes the contacts. Also, the reading should indicate “0” on the meter.
The 0-ohm reading is important; you may hear a click, but if you do not have continuity through the contacts, the solenoid is still faulty. If no reading is indicated, the solenoid has an “open.” If you read 0 ohms with no voltage applied, the solenoid is “shorted.” A short also may exist between any battery terminal and the casing itself. In either case, the solenoid should be replaced. If your coach is equipped with a larger, heavy-duty solenoid, the testing procedures are the same.
Water Line Cover-Up
DEAR RV DOCTOR:
I have a water leak that looks like it is coming from under the tub when I turned off the hot water tank bypass. Is there an easy way to access the water lines without destroying the inside of the bathroom? I think the damage was caused by mice chewing a hole in the water line. Please help!
Joe Linneman, Wentzville, Missouri
Joe, from a technical standpoint, one of the nice things about working on RVs is the relative ease with which some components can be exposed. Unfortunately, this fact does not apply in every instance. RV water lines can sometimes be difficult to locate. But, typically, by removing a panel or an accessible flooring section, one can successfully gain access to most of the fresh-water plumbing system.
The clue to a removable panel is to look for screws instead of staples holding it in place. And it’s quite common to find such a panel under or near a tub enclosure. In those instances when a removable panel does not exist, it is often possible to carefully cut an access hole and install a larger piece of like paneling trimmed with garnish to cover up that opening after the repair has been made. In other cases, a small access hole can be cut in order to facilitate the repair and then an aftermarket louvered vent secured to cover the hole. The fact is, if there is a water leak, you’ll have to gain access somehow, even if it means designing some type of cover-up afterward.
Air Conditioner Condensate
DEAR RV DOCTOR:
I have a Coleman air conditioner on the roof. I had a problem with water leaking inside through the air conditioner when it rained, so I sealed around the edges of the roof unit. I have since been told not to do that, that the condenser must drain onto the roof and now I will have that condensate coming inside. I removed the shroud but am unable to locate the hole or holes in the drain pan to see where it drains. Could you tell me where the holes are located so I can make sure they are clear and draining properly? The unit is so old that I am afraid to remove it to replace the 14-inch gasket.
Gus Tarver, Merritt Island, Florida
Gus, indeed the only water seal on the roof air conditioner occurs at the perimeter of the 14-inch opening. The air conditioner sits atop the 14-inch gasket only. Condensation must drain through the pan and onto the roof of the RV outside the 14-inch opening. The holes in the pan may be located under various internal components, making them hard to see by simply taking off the shroud. You may be able to find them by using a flashlight and a mirror, but they must be clear to allow the pan to drain. The fact that you have rainwater leaking under the air conditioner mandates that the unit be removed from the roof and a new gasket installed. It’s likely the constant weight and possible overtightening of the mounting bolts have compressed the gasket beyond usefulness.
Take off the interior shroud and the filters, and you should be able to see three mounting bolts that can be removed. These bolts sandwich the roof between the bottom of the air conditioner and the interior plenum. Be sure to disconnect the AC power before removing the plenum. Once the plenum is down inside the coach, the air conditioner can be carefully lifted off the 14-inch opening on the roof. Exercise caution when lifting the unit so that the roof material does not tear during the process. In fact, it’s best to use two people to remove the unit from the roof. Once exposed, the 14-inch opening can be cleaned and a new gasket installed. Do not overtighten the mounting bolts. You want to compress the gasket only enough to prevent leaks while securing the air conditioner.