@ waltraud I have never worked on a Westy fridge but I am guessing it is just the same as the usual "RM some number" ones fitted to most T25 campers. There should be some indication of the model somewhere on it, let "us" know and we can point you to a circuit diagram. Mind you, a person well versed in the use of a test meter set to Ohms could figure it out in minutes. Do you have a friend/workmate/drinking mate that knows about such things ? (though make sure he
knows and not that he just
says he knows
Ian and Lins wrote:to test for a 'drain' on the battery (either starter of leisure) I assume you disconnect the 12v 'live'/red and put a volt meter in series between the battery post and the terminal. If it reads 12v then something is taking current? What would the reading be if nothing is taking power/current?
To answer your question, it would in theory read 0 Volts. But, in the real world it would still read 12 Volts as there will always be a tiny drain and your meter, if set to Volts, is sensitive enough to read that tiny current and therefore display the voltage present.
However, read on...
That is not quite the way most folk would do it. Normally one would first set the meter to read DC Amps (not Volts). You would set it to the scale for Amps that says 200mA. You would then make sure everything in the van is turned off, radio, interior lights etc. You would then remove the +ve lead from the battery, hold the red lead of the meter onto the +ve terminal of the battery and the black one onto the lead you just took off, so the meter is now "completing" the circuit. You would then note down the reading. You will nearly always get some drain, from say the radio's memory wire, the clock, the alarm system, etc, but a reading of anything over 100mA indicates summat not really right. You then start taking fuses out, one at a time, to find out what is draining the power away.
Note, don't turn
anything on whilst the meter is in the circuit or you will either blow it's internal fuse, or even damage it more seriously.
Also note, some (better) meters have a 5 or 10 amp DC Amp scale. If yours has it, you can use that setting and then you can turn things on, but only things that use less than the setting, i.e., less than 5 Amps (or 10Amps). Of course, do NOT try and start the engine or your meter will go up in a puff of smoke !
Last note, the death of most multimeters often comes from folks making mistakes whilst it is set to Amps. Folk forget to set the dial to off and they forget to put the red lead back into the "Volts" socket. Then they go to measure the voltage of perhaps a leisure battery, and as soon as they touch the terminals the meter goes up in a puff of smoke (or the internal fuse blows).
So, best practice = always remove the test leads when you have finished and set the dial to "off".
Here endeth today's lesson.
