If you like RVs, you already know that a big part of RV fun is getting away from it all. You can simply pack up the RV and head out to kick back and relax without having to deal with the hassles of everyday life. These quiet, relaxing and memorable motorhome trips shouldn’t be compromised by something as simple as a 12 volt electrical problem ruining your vacation.
If you’ve been riding in an RV for some time, you already know that a good portion of your RV’s gadgets and accessories run on 12-volt DC power. 12-volt direct current or DC is electricity supplied by the RV’s batteries. DC electricity flows in one direction, from negative to positive. 12V DC electricity is stored in the RV’s batteries and supplies power to 12-volt-powered components, devices, and appliances.
These 12-volt devices include overhead lights, water pump, fans, furnace fan, range hood fan, LP gas leak detectors, stereos, 12-volt televisions, and refrigerator. when operating in LP gas mode. When you go camping, you trust these 12-volt items to work properly, especially if you’re dry camping with no hookups. So what do you do when one of these 12-volt items stops working?
As an example, let’s say we are dry camping and our 12 volt water pump stops working.
I’m convinced that just about anyone is capable of troubleshooting a 12V DC problem and, in many cases, repairing the problem without it ruining your camping trip. To get started, you’ll need a couple of simple tools to help you troubleshoot your RV’s 12-volt electrical system.
one). An inexpensive 12 volt test light.
two). A multimeter that can test DC power.
Both are available at local auto parts stores. You should also have electrical tape, various sized wire nuts, 12-volt light bulbs, and 12-volt fuses on hand. Check the amperage of the fuses used in the power distribution box and keep a stock. If you know of any in-line fuses used in any of the 12-volt devices, keep those handy as well.
Now try to determine the last time the water pump actually worked. Did you leave the RV for a period of time with the pump running? Is there water in the fresh water holding tank? Was he working on or near something else that could have affected the operation of the water pump? Try to think of all possible scenarios. Something might jog your memory and result in a quick fix to the problem.
If not, the first step is to check that the coach’s battery(ies) are sufficiently charged to supply power to these 12-volt items. There are a couple of ways to do a quick test on coach batteries. You can use the monitor panel to check the status of the bus batteries. To get an accurate reading, make sure the RV isn’t plugged into electricity and turn on a couple of dome lights to put a small charge on the battery. Check the reading on the monitor panel. (If you check the reading on the monitor panel when the RV is plugged into electricity, you will get a fully charged reading.) A more accurate method is to test the battery with a multimeter. Set the meter to read 12 VDC and place the negative test lead on the negative battery terminal and the positive test lead on the positive battery terminal. A fully charged battery will read in the range of 12.6 to 12.7 volts. If it reads less than 12 volts, it is below 50% state of charge and will need to be charged.
If the battery is fully charged, the next step is to make sure all bus battery disconnect switches are turned on. If the battery disconnect switch is on, check to make sure other 12-volt devices in the RV are working properly. If there is 12-volt power inside the RV, you should check the fuse for the water pump at the power distribution center. Determine which fuse is for the water pump (fuses are normally labeled) and find a suitable ground for the 12-volt test light. Test both sides of the fuse for 12 volt power. If the test light only comes on on one side of the fuse, replace it with the proper size fuse and retest the water pump. If there was power to both sides of the fuse, check for 12 volts at the water pump switch. If there is voltage and the switch is working properly, check the water pump wiring for an in-line fuse.
Find a good ground for the 12 volt test light and test the wire on both sides of the fuse. If there is only power to one side of the fuse, replace it with the proper size fuse and test the pump again. If there is power to both sides of the fuse, check the water pump wiring connections at the wire nuts. Connections may loosen due to excessive vibration. Correct loose connections and retest pump. If the pump still does not work, feel the motor to see if it is hot to the touch. If the motor is hot, a thermal switch may have tripped. Let the pump cool down and see if it resets.
If you complete all of these tests and get 12 volts DC to the water pump motor, and it still won’t start, the water pump is probably bad and needs to be replaced.
Troubleshooting a 12-volt electrical problem on your RV isn’t all that difficult. Follow the logical path of the device you are troubleshooting and see if you can determine where the problem is. You may be able to save your well-deserved vacation, some money, and a trip to the RV dealership, too.
Note: If you are not comfortable performing your own maintenance or troubleshooting the 12-volt electrical system, take your RV to a licensed repair facility for inspection and repair.
Copyright 2006 by Mark J. Polk owner of RV Education 101