buylow12 wrote:
Your probably the third person to say that so I figured I'd give it another thorough look. There are two vents, a lower one and an upper one. The upper one has what looks like a heat exchanger but there are no fans that I see. Looking through the manual it appears there is usually supposed to be a lower vent and a roof vent but I can't find any mention of fans. Obviously since it's in a slide it can't have a roof vent so that why there is an upper one. Maybe some models have them and others don't? Anywhere else I should look?
Well it was useful for finding out which circuit was drawing all those amps. From there I was able to find the problem splice. I also used the ohm setting on the multimeter a bit. Like I said this is the first time really using the multimeter so I'm just learning how to use the different settings. You say I should use the volt setting, what is the difference/advantage to that? When should you use one vs the other?
Tim Czarkowski
TotalTravelers.com
The upper vent is the equivalent of the roof vent for your fridge installation. Basically it's just an intake (at the bottom) and an exhaust (at the top), with airflow induced by the heat from the fridge...and aided, in your case, by fans, since the upper side vent isn't as effective as a roof vent.
As for what setting to use, it entirely depends on what you're measuring, which depends on what you're trying to find. Not very helpful, I realize. It does make more sense when you have a decent grasp on basic electric circuit theory.
It's not a perfect description, but voltage is basically electric pressure, and current is electric flow. (Imagine a water hose or plumbing system for comparison.) You measure voltage between two different points: how much pressure is the battery producing? Is the pressure at the terminal of the battery different than the pressure at the input to the fridge? Is the electricity reaching the light, or is it cut off by a switch or fuse or something on the way?
Current, on the other hand, is measured through some point in the circuit. This implies that (absent a clamp-on meter that works "magically" via magnetic phenomena) you need to take apart the circuit and make the current flow through the meter, or at least through a shunt that you can then attach the meter to.
It's comparatively rare that measuring current is all that useful as a first step in troubleshooting something in an RV. It is useful to see how much electricity you're using at the moment, or whether some is leaking out where you don't want or expect it to, but not quite so handy usually for a "it works/it doesn't" sort of investigation.
Resistance (Ohms) is a description of how the voltage and current relate to each other for a given resistance. In a water analogy, it's like measuring the effect of a kink or constriction in a hose; at a given pressure (drop), you get a certain flow, determined by the amount of constriction. Ideally you want your wires (pipes/hoses) to have no restriction and cause no pressure drop, so they should show no resistance. You don't want your electrons going where they don't belong, so there should be infinite resistance (an open circuit or complete blockage) between the inside of the wire and the stuff on the outside.
Since the way to measure resistance is to put some known voltage across the resistance and measure the current, or vice-versa, the ohm range does not work when the circuit is live.
