Hidden fuse? Fridge, radio, Co2, sensor panel out

[moffittclan]

I have a 2009 Jayco 17 Ex-Port.  Getting it ready and didn't have any 12 volt.  Found the inline fuse at the battery blown so I replaced that.  Everything came on except the Fridge, the radio, the little senor panel that shows the water levels,etc. and the Co2 sensor.  So these must all be on the same circuit but I can't find a wiring diagram.  Under one bed is the fuse center.  I reset all the breakers and pulled each of the 15 amp fuses and made sure they were good with a ohm meter.  I found a breaker under the fridge and reset it (though it wasn't blown).  I check the power on the back of the fridge and I have 110volt going to the fridge and 12volts (actually it reads as -12volts).  Finally, I unplugged the 110v from the camper to verify the 12v was powering lights and stuff and they were still good to go. 

So I can't find any other fuses in the camper but since multiple things (all requiring 12v aren't working, I'm missing something!  Any suggestions?  Camping in 2 days so need help ASAP!

 

[Henry J Fate]

Try to identify the 12 volt fuse in the panel that any of those devices are connected. Fuses should be labeled somewhere. Once you identify the circuit fuse, check to see if power is at the fuse holder.

 

[moffittclan]

Thank Henry.  I did find those and checked them but they were all good.

Followup, I found two more 30 amp fuses in the inverter buried under the bed.  It was awkward getting to them and they were in there tight.  I finally got one out but it fell apart coming out so I'll have to figure out how to remove the inverter to get the rest of the fuse out.  It does look like it has a burn mark so I'm hopeful that's it.  I plugged the unit back into 110 and even without the second fuse, everything that worked before still worked and the things that didn't work (Co2, fridge, etc.), still didn't work.  So hopefully I've figured out the issue and just need to figure out how to get the inverter out.

 

[Henry J Fate]

Even with the bad fuse in the converter, 12 volt power should be available from the battery. It sounds like you had a pretty good electrical event to blow both the battery fuse and the converter fuse. While you have the converter out, take off the cover and take a good look inside to see if anything looks overheated. Before you take the converter out, be sure you are not plugged into shore power and disconnect the battery.

 

[Gary RV_Wizard]

Those two fuses in the inverter (more likely a converter?) are there to protect from reversed polarity on the battery connections, so they probably dies doing their job. A momentary mistake while installing or removing batteries or cleaning the terminals can op those fuses and the amp surge can be enough to literally fry them.  The two fuses act in concert, so both have to be good. 

You mentioned seeing -12v and also blew the polarity fuses.  Take a good look at your batteries and make sure the positive and negative cable connects are correct. The battery negative should be going to chassis ground.  Lighting will work with polarity reversed, but most circuit boards will not.  Friidge, detector and radio would clearly fall into that category.


Depending on the 12v system design, blown primary fuses in the converter can indeed cause full or partial power loss, but it appears that most of your 12v is wired direct to the battery (the stuff that works now).

By the way, you don't have a CO2 detector. You should have a LP gas detector and a CO (carbon monoxide) detector. And you probably have a CON verter (makes 12vdc from 120vac) rather than an INverter. An inverter produces 120v power from a battery when no external (shore) power is available.

 

[moffittclan]

Gary,
  Thanks for all the notes and corrections.  I mean that sincerely.  I'd rather someone educate me than to allow me to continue to be wrong.

I did fix the issue.  I removed the converter (a bit of pain to get to) and sure enough both the 30amp fuses were blown.  The other thing that surprised me was that the fuses were being held in on a busbar with screws that, when tightened, cinch them in there good!  So I had to loosen the screws before the old fuses would come out.  While doing all this I also checked the AC cables coming to the converter and the ground was a little loose (might have been the original cause?).  Anway, it's all back together and everything is running now!  I appreciate the assistance and wanted to close the loop incase someone else had a similar problem in the future.

Mike

 

[grashley]

Now I'm confused.  What fixed the issue?  Was it caused by the blown converter fuses only?  I would have expected those items to be fed from the battery.  Those fuses would prevent the battery from charging, so maybe the battery voltage was too low for those items to function?

 

[moffittclan]

The battery was brand new and ran the lights and water pump even before I fixed it.  Only thing I could figure was that the 12v circuit for the items not working might route through the converter.  I don't know but I know for sure that's what fixed it.  I get your train of thought though, that's why it took me a while to even look at the converter for any issues.

 

[Rene T]

After what Gary said, I take it that you checked the battery cables for being hooked up correctly. Negative cable is connected to the RV frame work. Most times the cable is white but don't rely on that color being ground. Yours could be a different color.

 

[ChasA]

Rene, with all due respect. Negative battery cables are usually  black and postive are usually  red. I have never seen a white battery cable. Now if you're looking at some fixture such as a light, those negative wires may be white or they may be black.

 

[Rene T]

Rene, with all due respect. Negative battery cables are usually  black and postive are usually  red. I have never seen a white battery cable. Now if you're looking at some fixture such as a light, those negative wires may be white or they may be black.

My white wire is negative and the black is positive. I don't have any red wires. The OP just has to check.