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Lumatic · 05-21-2007, 01:04 PM

Until yesterday both by 110 and 12v were fine. Today the 12v system works only when connected to shore power and does not work at all when not connected to shore power. The battery voltage is 12.89v If I disconnect the battery the leads show no voltage coming in. The control panel battery meter reads 0 when the shore power is off. I replaced 1 12v burned out fuse but it doesn't make any difference. Any ideas what I should check, or is this 35 year old univolt finally toasted?

AYRSTRM2 · 05-21-2007, 01:18 PM

It's not your univolt, probably. You would still be getting 12 vdc power. Likely there's more fuses blown. If you haven't done so, get and replace all of your fuses in you panel. Also, check you fuses by or in the Univolt for blown fuses. Also, look for a disconnect in the ground somewhere, that would possibly create the situation you are describing.

Excella CM · 05-21-2007, 04:00 PM

Here's the logic:
1) If you have 12vdc on shore power, the circuitry and the univolt are OK.

2) Since the battery shows voltage, there must be a disconnect between where the battey(s) hook up and where the univolt hooks in. Look carefully at the battery terminals and where the battery cables go to ground and to the positive buss in the control panel

guy99 · 05-21-2007, 06:11 PM

I'd suggest that you put the positive probe on your meter on the Positive (+ Red), post of your battery, then touch the negative (- black) probe of the meter to the chassis of your coach. If you don't get essentially the same voltage as when you put both probes on the battery, you have a ground problem.

Lumatic · 05-21-2007, 07:01 PM

Found the varmint, I think

The fuse that was burned out that I mentioned earlier was the one for the car battery connection it was supposed to be 40 amps, the PO put in only 20. do you think that had something to do with it blowing? Really?

But I think the real varmint was the 40 amp fuse for the coach battery. I took out all the fuses and VISUALLY inspected them. It looked OK so I put it back............... I just tested it and it has no continuity, duhhhh.

Thanks for the other answers. Got me going in the right direction this time. And some helpful hints.

The acid test is when the parts store opens and I get another fuse.

68 Overlander · 05-21-2007, 07:33 PM

Those fuses are probably AGU and getting harder to find in 40 and 50 amp but they are out there. I never see them in hardware stores or auto parts stores any more but maybe you will get lucky at an RV parts store. Many of them stock them. If you can't find them, let me know and I'll send you a couple for just the postage.

Lumatic · 05-21-2007, 08:10 PM

Quote:

Originally Posted by 68 Overlander

Those fuses are probably AGU and getting harder to find in 40 and 50 amp but they are out there. I never see them in hardware stores or auto parts stores any more but maybe you will get lucky at an RV parts store. Many of them stock them. If you can't find them, let me know and I'll send you a couple for just the postage.

I had a sneaking suspicion about that

I will check with my next door neighbor the town auto parts store, but I think I will not find them locally. I'll let you know tomorrow.