APPLICATION: This procedure applies to non-Vanagon Westfalia refrigerators of the late 1970s. These refrigerators can be operated either on 12v battery power or on 110v shore power via a power converter under the rear seat that converts 110v AC to 12v (really 14.5v or so) DC.
Late Westies, like my '79, have one 12v heating element for the refrigerator which either gets 12v from the auxiliary battery or from the power converter. Some earlier models apparently have both 110v and 12v heating elements. I'm not sure if this article applies to those. It certainly does not apply to Vanagon Westy refrigerators which can run on either 110v, 12v, or propane. While the principle is the same, the wiring is much different.
The procedure below is designed to troubleshoot a non-working refrigerator. It leads you through the wiring step by step so you can narrow the trouble down and hopefully figure out what you need to do to get your fridge working again. This procedure was written by Karl von Salzen and is reprinted here with his permission.
I'll also note that there is a fuse at the converter that is apparently not well-known. The converter can be found under the rear seat, toward the driver's side. It is under a wooden cover that you can remove by undoing two screws. The converter has, at the rear, a hinged flap with a screw holding it on at the non-hinged side. It's easiest to see this if you remove the converter (undo the four fasteners that hold it to the floor) and then get to the rear that way. Undo the screw and open the hinge and you will find a fuse holder. You will also find out that it is a 15A power converter made in Kokomo, Indiana. Anyway, this fuse was slightly dead on my converter and was causing weirdness. One of the ends on the fuse (it is an American car type fuse, AGC style -- the glass tube fuse) had separated from the fuse and was only loosely in contact. So I would get a nice voltage from the converter but the fridge would not work and neither would the battery charger. So the procedure below really didn't pinpoint that particular problem since the procedure is based on voltages, which read OK. However, due to the fuse, the fridge was unable to draw a current and so didn't work. I found the fuse totally by accident and replacing it (it is a 20A and 32v fuse) saved me from buying a replacement converter, which I was about to do. Replacing the fuse got my fridge working on 110v again (it worked OK on battery, but I couldn't figure out why it didn't work on 110v). But I hope this helps someone in case they run into this.
Begin Karl's procedure:
Look at your converter -- it has a Romex cable from breaker box to right rear corner. Out of left rear corner are three wires -- 2 white + 1 red. The red one is power out with breaker on. You should have 0 volts with breaker off. Flip breaker and you should have 14.5 volts. If you do converter works -- if you don't, replace it.
If you have voltage take out the 4 screws and lay the control panel face down.
You should have 4 wires coming up to it from the rear:
1 white to top of bat test light.
1 red from converter to top terminal of timer.
1 black to bottom of timer (goes to positive terminal of left battery).
1 blue center terminal of fuse (goes to thermostat under grille).
The black wire at bottom of timer should read at least 12v. Same as left battery positive terminal voltage. This wire continues on to the top terminal of the city power switch and to the bottom terminal of the battery condition switch.
The red wire at the top terminal of the timer goes on to the bottom terminal of the city power switch.
At the middle terminal of the city power switch is another red wire -- it goes to the bottom terminal of refrigerator switch.
At the top terminal of refrigerator switch there are 2 blue wires -- one goes to the base of the fuse -- the other goes to the bottom terminal of the refrigerator light.
The top terminal of the batttery condition switch has a short black wire that goes to the meter. Out the other end of the meter is a short white wire -- it goes to the top terminal of the refrigerator light (it continues on out the body with the other 3 wires).
Are you totally lost yet? I hope not --
Now if all the wiring is correct get the voltmeter back out. Go to the bottom terminal of the meter (black wire). You should have 12v from left battery.
With breaker off and timer off check voltage at top terminal of timer (red wire). You should have 0 volts. Flip breaker on -- you should have the same 14.5 volts you had coming out of the converter. If you don't, check at the converter again. If it's at the converter but not at the timer you have a broken red wire between the converter and the timer.
If the voltage is there turn the timer on -- you should get 16.5 volts at the red wire and thru the timer out the black wire back to the battery. The meter should also peg to the end of the green section (charging). Turn the timer off -- voltage should drop to 14.5 volts. Go to the refrigerator switch -- bottom terminal (red wire) should be 14.5 volts.
If not go back to the center terminal of the city power switch -- should be 14.5 volts (turn city power switch to city power). 0 volts = bad city power switch. 14.5 volts = broken wire between city power switch and refrigerator switch. If you have 14.5 volts at the bottom terminal of refrigerator switch turn on switch -- you should have 14.5 volts out the top terminal (blue wire) going to the base of the fuse. You should have 14.5 volts coming out the center terminal of the fuse and going to the thermostat. If you do it should work on 110v.