12 Volt Electrical Problem

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jhall

Member
Joined
Aug 26, 2012
Posts
6
I have a 1982 Winnebago 621. The 12 volt system will not operate anything on it's own. When it is plugged in, everything works fine. Unplug the 110v and everything stops instantly. I checked the batteries with a voltmeter, and had 12v across both batteries. I went to the fuse box 12 v across the main fuse at the base of the box,and continuity across each of the fuses. Just to make sure the batteries were fully charging, I used the aux. batteries to start the engine. Which it did without a problem.
I guess the thing I am looking for, is the next step, or the one I missed. If someone has had a similar problem, or advice, I would appreciate it.
Thanks, Joe
 
jhall said:
I have a 1982 Winnebago 621. The 12 volt system will not operate anything on it's own. When it is plugged in, everything works fine. Unplug the 110v and everything stops instantly. I checked the batteries with a voltmeter, and had 12v across both batteries. I went to the fuse box 12 v across the main fuse at the base of the box,and continuity across each of the fuses. Just to make sure the batteries were fully charging, I used the aux. batteries to start the engine. Which it did without a problem.
I guess the thing I am looking for, is the next step, or the one I missed. If someone has had a similar problem, or advice, I would appreciate it.
Thanks, Joe
Did you measure the battery voltage with all the 12 volt stuff on while NOT working?

Perhaps the Aux start is  using the chassis battery as well as the house batteries and that's why it still cranks on Aux.

Seeing 12 volts is rather meaningless if you're not drawing current from  a load.

And check from the connectors or wire down from the battery if possible, to make sure it's not a bad connection near the batteries which is quite common. And see if the positive wire goes to a solenoid and see if it's got juice on both sides.

And if you have six volt batteries, be sure to check the connection between them that goes from neg of one battery to the pos of the other.

-Don-  Reno, NV
 
It seems clear the battery power isn't reaching the distribution panel - only the converter/charger output is. Yet you say you can measure 12v there?  That doesn't make sense. Did you measure at the distribution panel (fuses) when shore power was disconnected?

Your loss of 12v power symptoms indicate that the cable to the battery(s) isn't making contact or that the battery(s) are dead. You say they have voltage, so that leaves the cable connections. There may be an inline fuse on the cable as well.

Using Aux Start doesn't prove anything unless the chassis batteries were offline. Aux puts the house and chassis in parallel, so both sources contribute to cranking. The chassis batteries would start the engine even if the house batteries were helping.
 
Did you really mean that you had 12V ACROSS the main fuse, or was it 12V from the fuse to ground?

That fuse will either be open, or it will have very low (well under1 ohm) resistance. If the fuse is intact, there should only be a few millivolts across it. If it really has 12 volts across it, it is blown.
 
Hi Guys,
John, I have had it for about 5 years. Before that it sat in a field about 20 years.

GHO it was 12v from main fuse to ground. I double checked each of the fuses and they were fine and there was 0 v across them.

I took both batteries offline and tested each with a battery tester, and load tested them, both were fine.
I am thinking at this point it is the solenoid, the cables from the batteries to the solenoid look in good shape and show continuity. If there are any other ideas I would love to hear them.
Thanks, Joe
 
It's sounding more and more like an issue with a house battery disconnect solenoid.  I am completely unfamiliar with a rig of your vintage, Winnebago Owner Relations might be able to email you a 12v wiring diagram.
 
Do you think that it would do more harm than good to jump out the solenoid and see if we get power?
 
Shouldn't do any harm. The biggest problem would be arching when you touch it. If you have a battery switch you could turn the battery off and then connect the jumper, then turn on the battery switch.
 
John Hilley said:
Shouldn't do any harm. The biggest problem would be arching when you touch it. If you have a battery switch you could turn the battery off and then connect the jumper, then turn on the battery switch.
Have you checked to see if there is voltage on the coil of the solenoid when the house stuff is turned on? As well as voltage (at all times) on the input side of the solenoid?

-Don-  Cold Springs Valley, NV
 
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