New battery not powering 12V interior lights

Discussion in 'Wiring' started by qswv, May 30, 2010.

  1. qswv

    qswv Member

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    Thanks to all. The inline fuse on the pos wire is OK--not blown and registering proper resistance. The 2001 Taos is an auto-switch from shore to battery (hence no actual switch to perform that function.

    I will check the 12V power at the back of the converter. The problem is that to trace the wire from the battery to the converter requires pulling it from the frame of the camper...If this has to be done, and I found a fray, would I then try to replace the new wire back into the frame (chassis)??

    Thanks again to everyone's helpful suggestions! More soon.
     
  2. Unstable_Tripod

    Unstable_Tripod Well, there's your problem!

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    You might consider attaching a fish tape to the wire when you disconnect it and then when you pull it out you will pull the fish tape in. You can reverse the process to get the old wire back if it's OK or the new one in if you need to replace it.
     
  3. Woodzeke

    Woodzeke New Member

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    A cheap fish tape can be had from harbor freight for less than 10 bucks, or you can tape a new wire to the old and pull it through. To ID the wires going to the converter, have someone pull on the wires at the tongue while you watch at the converter. My bet is still a bad ground or maybe resetable circuit breaker or in line fuse near the battery.
     
  4. rabird

    rabird Howdy!

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    Don't get ahead of yourself.

    Make sure there is 12v going into the PU at the back of the converter.
    here's a pic of the back of a more modern Coleman using a WFCO 8725.
    [​IMG]

    If you have a connector, unplug and measure the voltage between the corresponding pins that become the red and white wires.
     
  5. ogeer3

    ogeer3 New Member

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    Just measure the voltage on the red wire at the back of the converter. The chassis of your camper may not be ground for the 12v so use the ground return wire at the converter for your reference. Don't start following wires under the camper until you have to.
     
  6. dannyoung

    dannyoung New Member

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    You are going to need a digital multimeter and you will need to remove the metal faceplate from the converter for some of the following.

    1. Plug in the trailer to shore power and check voltage across battery terminals
    a. If the reading is 13 to 14 volts go to step 4
    b. If the reading is 12.5 volts or less go to step 2

    2. The converter is not charging, either because
    a. It is not a charging unit and needs a separate charger - check make and model specs
    b. There is a short in either the ground or the + side – go to step 3
    c. The charging component is faulty or a fuse is blown – go to step 5

    3. Maybe there is a short. You will very likely need to take the cover off the unit to get at some of these test points, and it goes without saying that you should make sure to disconnect the battery and all power sources when testing for continuity.
    a. Ground Test - using your multimeter check between the end of the ground wire that attaches to your battery and the frame of the trailer. You should get a reading of 0 if all is well; if not, you've likely found your problem…replace the ground wire.
    b. Positive Test – using your multimeter test between the end of the cable that attaches to the positive terminal on the battery and the point inside the converter unit where the battery cable starts it journey; right where it’s soldered to the board if you can. If you don’t get a reading of 0 than your problem lies there and you need to recheck the circuit for hidden switches and blown fuses; if you find none, than you will need to replace the circuit. If you have to replace the wire, make sure to put in an inline fuse and battery shutoff. If all reads fine than see step 5

    4. Your charging voltage reads 13-14 volts, but your 12 volt items aren’t working. If the unit automatically switches between converter 12V and battery 12V then either a fuse is blown (there are generally no internal fuses) or the device is faulty. The connection between the battery circuit and the 12V item circuits in your trailer are contained entirely within the converter; If there are no blown fuses then you should see step 5
    If it isn’t an auto switching unit than check again for switches, none…see step 5

    5. You've checked all the fuses right, check again, replace them regardless and use your multimeter to check continuity of each circuit, sometimes the problem is not the fuse, but the fuse holder. You've checked the continuity of the ground and positive circuits to the battery. If it still isn’t working than a new WFCO converter charger is only $100


    Don’t forget to the check the continuity of all the switches in your trailer as well. If there is a safety switch under the sink it may need to be replaced or eliminated. I actually placed a master shutoff switch with and indicator light right beside the trailer door, so it’s the final thing to do when I close up the trailer…Good Luck
     
  7. qswv

    qswv Member

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    OK. Thanks for everyone for their helpful troubleshooting tips. To recap, my nbrand new interstate battery is not powering the interior lights, LP detector, or furnace, but these items are working fine when on shore power. The battery reads 13V. Also, the shutoff switch underneath the galley is working properly when on SP. Here's what I've found out thus far with everyone's guidance.

    One clarifying question first. In Rabird's photo of the back of the converter (shown above), I assuming that power enters the converter from the battery via the white heavy duty wires/cables--one of which enters the back of the converter and the other enters at the side. I'm also assuming that the grouped colored wires deliver power from the converter to the popup. Is this correct?

    Rabird, you mentioned to "Make sure there is 12v going into the PU at the back of the converter...If you have a connector, unplug and measure the voltage between the corresponding pins that become the red and white wires." When the popup was on shore power, the pins that become the red and white wires were reading 14V. However, when shore power was disengaged and the battery was attached, these pins did not register any DC voltage. Thoughts on this?

    Dannyoung, thanks for your detailed walk-thru. Here is what I found out. When on shore power, the battery terminals read 14V DC. So I went to step #4. All fuses are intact are functioning correctly when the popup is on shore power (ie, when the 15A fuse is pulled that powers the interior lights, the lights go off)..I am unsure how to "check continuity of each circuit". Can I accomplish this with Ohms on the multimeter.

    So, does this info point to a bad converter? or is there an in-line fuse somewhere in the line b/t the battery and the converter that I cannot see? The fuse near the + terminal is working properly, as are the 4 15A fuses in the actual converter.

    Thanks again for everyone's help. I hope I can isolate the problem w/o paying an over-rated, super-expensive RV tech to troubleshoot this at $110/hr. I can post a picture of the back of my converter (2001 Coleman Taos) if people believe it will help.

    THANKS!
     
  8. Taxus812

    Taxus812 Member

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  9. maxou723

    maxou723 New Member

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    Hi I just experienced the same problem today with my StartCraft popup.

    Finally what was the outcome for you? What finally was the problem?

    Steven
     

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