Switch or Solenoid

We sure enjoy your column, but in an earlier one, even though you gave a very thorough answer about 12-volts DC troubleshooting, you forgot one thing. That is to check the male and female connectors hooking a towed car to the motorhome. Several years ago I had similar troubles and the wires in the connectors were all broken and shorted due to moisture and dissimilar metal corrosion. The wire was copper and the connector lugs were steel. I replaced the connectors with ones with copper lugs and packed the internals with grease. Worked great! I do have an electrical problem I would like your advice on. One of the two battery disconnect solenoids isn't working anymore. The switch has six terminals on it and each has a wire connected to them. The solenoid is almost impossible to see let alone get a multi-meter connected. Do you have any suggestions on how to determine which is bad, the switch or the solenoid?
Jim, (Bellevue, WA)

Jim, thanks for the comments on that earlier question; good additional information for our readers. Now, onto your issue. Assuming you have an Intellitec battery disconnect system, my first inclination is that one or both of the fuses on the solenoid is blown. There should be two fuses mounted on top of each battery solenoid and it appears it's time to check them for continuity. Although you have indicated difficulty in accessing the solenoids, you should be able to feel for the fuses in order to remove and check them. Since you can't readily see or access the solenoids, you can attempt to troubleshoot the problem from behind the switch panel. Turn both switches to the "use" or “connect” position.

Since you did not indicate which solenoid was not switching, try the following. If the coach battery is not switching, check for 12-volt DC between the white and brown wires. If the problem is with the chassis solenoid, check for 12-volts between the gray and purple wires. If you have a nominal 12-volts present at these wires but the solenoid is not switching, then there is either a wiring or connection problem, or the solenoid itself is faulty. If you have no voltage at either of those two sets of wires, there is a problem with the switch or control board. If this is the case, turn off the switches and swap the wiring between the two switches, one at a time, being very careful not to mix up the wire positions. Hint: Label each one before removing them. Turn the switches back on and check to see whether the solenoid that wasn't working is functioning now. If so, you have a faulty switch. If the same solenoid still doesn't work, then the solenoid is faulty and needs to be replaced. Any other problem would likely indicate a problem with the control panel itself. Remember to return the switch wiring to their original positions.

How to find drain on RV batteries

How can I test if I have a drain on my batteries that I am not aware of once I disconnect my land-line power and switch over to DC power?
Will, (Jacksonville, FL)

Will, there are a couple of worthwhile methods owners can choose for testing the battery system for a drain. Begin by making sure the shoreline cord is unplugged and that all 12-volt components are turned off. The easiest way to check for a battery drain is to use a clamp-on DC ammeter. This device clamps around one of the battery cables and reads directly in amps or milliamps depending on the size of the current drain. The nice thing about the DC ammeter is that no wiring needs to be disconnected.

Another method invokes the use of a volt, Ohm, multimeter (VOM). Most RVers will carry a VOM for measuring voltage, but many quality VOMs will have an “amp” scale for measuring DC current. Begin by setting the VOM to the 10-amp scale and then remove the negative cable from the battery. The result is an open DC circuit. Connect the red test lead from the VOM to the cable you just disconnected and the black test lead to the negative terminal on the battery itself. Now you have a complete circuit with the meter inserted in series with the negative cable. If a battery drain exists you will see a draw on the battery measured in amps or milliamps.There are a few parasitic drains on both battery systems that are considered normal if they fall within the acceptable standard of around 100mA or less (about one-tenth of one amp).

Next, make certain all 12-volt appliances, lamps, etc., are indeed turned off; don’t forget those lamps inside storage bays or other out-of-the-way locations! If the drain persists, go to the DC fuse panel and remove each fuse, one fuse at a time. If the drain disappears when a particular fuse is removed, the meter will indicate zero. When that happens, you’ll know that fuse is protecting the circuit which contains the component draining the battery. If your circuits are labeled somewhat nebulously, you may need to launch a more finite search. Here’s an example: Say the VOM indicated a fuse labeled, “Right Side,” indicating that circuit is situated on the right side of the RV. Now you have at least eliminated the left side and narrowed the search to just those 12-volt items on the right side of the coach. One by one, seek out every 12-volt item. Work from one end to the other in a systematic way.

In one troubleshooting case I finally found that the booster for the TV antenna was inadvertently left in the “on” position creating a small draw that eventually drained the battery. Turning it off, the measured drain on the meter fell to within the acceptable standard. It’s a matter of eliminating those “good” circuits in order to find the “faulty” circuit and component.

RV Holding Tank Valve

I have a 1974 Prowler trailer. I think the black water valve leaks liquid because only solids remain after several days of use. I purchased a retrofit valve but on inspection I don't see how this new valve can be water tight. The slide in the valve does not touch the rubber seals all the way around. On installation do the seals compress and contact the slide valve or do I just have a defective design? My trailer is in a remote area so I want to make sure I have all my ducks in a row before I tackle this nasty job. Your advice is very much appreciated. Thanks.
Pat, (Carrollton, TX)

Pat, the termination valve itself is but 1/5 of the total package that ensures a leak-free termination assembly. As you’ve noticed, the slide itself appears to not reach the top or bottom of the valve. On your waste drain plumbing, you’ll find two adapters which sandwich the valve between them. It’s this sandwich, with the seals on the two adapters that create the leak-free seal. The valve itself must be a full-way valve, meaning the valve must have a full three-inch diameter when fully opened. Therefore, the seals must be located beyond this 3-inch diameter, hence the adapters on each side of the valve.

When you remove the old valve, you’ll see the adapters. It’s okay to use the same adapter fittings, but be sure to use new seals. Lightly coat each seal with a lubricant (I recommend Dow Corning’s 111 seal grease) and place them on the lip of each adapter fitting. Taking care not to disturb the seals, carefully insert the new termination valve between the adapters and secure with the four bolts. Snug all four bolts down finger-tight and tighten them in diagonal corners. Take care not to over tighten them. Do not crack the adapter fittings around the bolt heads or nuts.

But since you are going to this trouble, you may want to consider installing a 12-volt electric waste valve instead of the manual type. Check out this valve! Having the electric gate valve will enable you to open and close it from inside the RV with the simple push of a switch. It installs in the same manner as above. Take a look and see what you think.

Ever Nagging RV Batteries

I own an older Coachman motorhome. I have a problem with the charging system. When I plug the RV into an electric outlet my auxiliary battery becomes overheated (very hot) with a strong sulfur smell. This has happened numerous times and every time I have to disconnect the battery so that it doesn't blow up. I have had the RV to a technician and he removed the converter and had it checked out. I removed the solenoid located behind the battery on the fender and had it checked. Any information that you can provide would be greatly appreciated.
Kevin, (Eveleth, MN) 

Kevin, I’m sure you’ll agree, battery problems seem to ever nag us. The first step in troubleshooting any problem with an RV battery system is to analyze the battery itself. Sulfated batteries simply will not hold a charge and are prone to overheating while charging. The degree of sulfation is also proportionate to its ability to hold a charge. All batteries self-discharge, but sulfated plates quicken the rate. 

See if your local RV service shop has a carbon-pile battery load tester. This test will provide insight to the internal happenings of the battery. Clean and tight electrical connections are also extremely important. Corrosive terminals and faulty connections all lead to early current loss. Don't overlook the negative side of DC circuits as well. 

Additionally, older motorhomes are notorious for employing mediocre or even inadequate charging systems. The alternators and converter/chargers of old did not have the technical algorithms available today for proper and complete automatic battery charging. Rarely did the batteries ever reach full charge unless plugged into shore power for a very long time. Some were quick to reach an overheated charge rate; I suspect this issue with yours. 

Tests should also be performed on the battery circuits to determine if any current loss exists. Some small, parasitic drains are normal, but when current losses approach 700-800 milli-amps, something needs to be rectified. Obviously, a larger drain on a battery is even worse. Any Certified Technician can easily perform this test for you, but if you have a good, quality multi-meter, you can even do it yourself. Consider ordering my video, "Testing the Battery Systems - the Basics." 

There is good news, however. Today there are aftermarket alternators and chargers (available on-lne or at your local RV parts dealer) that increase the RVers ability to extend the electrical life in the batteries. Also, newer battery technology has improved battery performance and has minimized over-charging risks. It should be a consideration for all "serious" RVers of older coaches to upgrade to high-tech batteries, sophisticated three-step chargers and high output automotive alternators. Electrical woes will certainly be minimized and under proper usage, completely eliminated.