RV Doctor Column RV Doctor #275 Dear RV Doc, I have a 1984 Terry by Fleetwood, 30-foot, pull behind travel trailer with electric brakes. The problem we are having is with the brakes. The brakes will engage when pulling it even though we do not have the brakes hooked up in the plug-in on the back of the truck. We unhooked the battery on the trailer and do not have this problem but it is not safe to tow the trailer without the brakes. What could be the problem? Tammy Eggen, (Laure, TX) Tammy, all travel trailers equipped with electric brakes must also be outfitted with an emergency break-away switch. The purpose of this switch is to engage the trailer's brakes if the tow vehicle and trailer should ever become uncoupled while traveling down the highway. The applied brakes will stop the travel trailer eventually and avoid having a "runaway" vehicle bouncing down the road. The power for this switch comes from the trailer battery which is why your symptoms disappear when that battery is disconnected. The switch should be located at or near the tongue of the trailer and consist of box-like device with a removable pin fully inserted in the switch. The pin will also be equipped with a long cable that attaches to the ball on the hitch of the tow vehicle. When the pin is pulled, (picture a hand grenade), the switch closes and voltage is allowed to pass to the electric brakes on the trailer. Either your pin has been pulled, or is not fully seated in position or the switch is faulty. They are relatively inexpensive and should be tested from time to time. Being exposed to the elements mounted on the "A" frame of the trailer does somewhat shorten its life. If the pin and the cable attaching it are missing, a complete new switch should be installed. To test a break-away switch, jack up one side of the trailer and have a partner spin the tires on that side. The tow vehicle does not need to be connected for this test; a healthy battery on the trailer does however. While they are spinning, pull the pin from the break-away switch; the brakes should immediately lock up. If they do not, there is an open in that circuit and further troubleshooting is in order. Jack up the opposite side and try the same test. Never tow without a fully functional break-away switch. Dear Gary, I had a new Suburban water heater installed by an authorized dealer. It is a simple gas/electric model with no fancy relighting feature, etc. It smoked a bunch so I called Suburban and they sent me a new burner which I had installed. I had trouble lighting it and keeping it lit. The dealer that sold it to me made some adjustments. We went south and are still having trouble keeping it lit. I had a repairman look at it and he checked gas pressure, cleaned the burner and it still acted up. Seemed when we closed the door it sounded like it wasn't getting enough air and would die out. He bent the bottom hinges out to let in more air but it still sounded like it was going out from lack of air. Then he wired the door open so there was about a 2" gap at the top. Even with the desert winds it has remained lit. This is fine except for when it rains. Do you have any idea what we will have to do to run my water heater with the door closed? George Blair, (Marion, IA) George, I would have to first question the burner orifices in your water heater. It's obviously starving for air which would indicate too much gas flow. If the pressure is correct as you state, then the only other components in the system that affects the LP flow are the orifice openings; assuming the pressure test was done at the water heater. If the over-rich condition causes the main burner flame to go out, check that orifice for roundness and for the correct size. If it's the pilot flame being air-starved into oblivion, check to be sure it has not been damaged by something being poked into it. Orifices should only be cleaned by soaking them in acetone or a like substance and then allowed to air dry or in some cases, blown dry with clean compressed air. It's quite possible a technician inadvertently distorted the orifice opening while attempting to clear a purported blockage. The correct pilot flame is one which encompasses only about 3/8" of the very tip of the thermocouple. The air shutter adjustment, additionally, should be positioned to a point where you can audibly hear the main burner roar to about five feet from the furnace and closer in. The flame should be mostly blue with some orange tinges. You might also want to check where you purchased that last tankful of LP. See if they have a Material Safety Data Sheet or a spec that details how much butane is in the mixture. Though not probable unless you are having combustion problems with the other appliances, there is an outside chance it is fuel-related. Also, if you send me the full model and serial numbers I can check the orifice sizes for you. Dear Doc, we have a 1991 Terry, 24C travel trailer that we would like to equip with an air conditioning unit. I believe that it's pre-wired because of the dummy plate in the ceiling. I would like to know what size of unit would be adequate for cooling and also which brands might be better than others. Local dealers have given me many brand names to consider, but wonder what your preference is. Any other helpful info regarding roof-top air conditioning units would be greatly appreciated. Raymond Seifert, (Richmond, BC) Raymond, indeed there should be a dedicated air conditioner circuit behind that blank cover plate. If I remember correctly, the Romex cable is routed from that ceiling box to a point just behind the circuit breaker panel down below. First, remove any source of 120-volts electricity to the RV. You will need to add a 20-amp circuit breaker to the panel. It may be necessary to first remove one of the blank covers on the panelboard. Then simply connect the black wire to the breaker, the neutral white wire to the neutral buss bar and the ground wire to the ground buss in the panelboard. On the roof and at the ceiling, remove the existing 14-inch crank-up vent and the interior bezel. Drill a ½" hole through the side of the opening over to the existing ceiling box. You will also have to add a short piece of Romex wire from the ceiling box to the makeup box on the roof A/C ceiling panel; all in all, a very common add-on. As to brand names, I really have no preference, but a unit rated at 13,500 BTU's will more than adequately cool your travel trailer.
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