RESOLVED: [email protected] 320S not getting power from the tow vehicle

GibWGibW Posts: 77Member
2017 [email protected] 320 S.  Not receiving a charge when hooked up to the TV’s 7-pin. Tested the TV with a multimeter and all is good there. 7-pin plugs are clean. Battery cutoff is turned on and battery fuse is good. Tested fuse holder as directed by dealer with multimeter and showing a charge on the battery side but nothing on the other side. Checked the junction box under the trailer and all looks good.  Thoughts for trouble shooting?

Resolution... I took the trailer to our dealer, Elk River RV (MN). They found an intermittent short in a fuse holder on the 12V power line coming from the TV's battery. They replaced the fuse holder and now it works. Also, learned that the TV's lights must be on in order for the TV to deliver 13.7 volts for charging. A shout out to the crew at Elk River - they provided EXCELLENT service, working us in to their already booked schedule. We are so glad we bought our [email protected] from them. Thanks also to all on the forum and [email protected] Facebook page who weighed in with diagnostics/solutions.
2017 [email protected] Max-S, silver & silver, towed by a Titanium Silver 2018 Kia Sorento AWD V-6, Twin Cities MN

Comments

  • Sharon_is_SAMSharon_is_SAM Posts: 4,310Moderator
    Looks like the TaB 7 pin cable is at fault.  Sometimes the pins can bend just slightly enough to prevent contact.  Check out the 12 V pin at 11:00.
    Sharon / 2017 [email protected] CSS / 2015 Toyota Sienna Minivan / Cleveland Heights, Ohio
       
                                           
  • GibWGibW Posts: 77Member
    Sharon_is_SAM...Thx.  Will do
    2017 [email protected] Max-S, silver & silver, towed by a Titanium Silver 2018 Kia Sorento AWD V-6, Twin Cities MN
  • ScottGScottG Posts: 3,039Moderator
    Bumping this just to call attention to the edited original post which describes the resolution. Thanks for the followup, GibW!
  • lkc001lkc001 Posts: 339Member
    Post this as another good dealer to do business with!
    2016 Nissan Frontier SV V6 4x4
    Finally!  New Owner of a 2017 Tab 320S! 
    Woohoo!
  • BaylissBayliss Posts: 253Member
    @GibW, it seems odd that your tow vehicle lights must be "on" for it to deliver 13.7v to charge the trailer battery.  Did your dealer provide any explanation as to why that is?  I don't turn on my lights on my 2007 Toyota Tundra while towing and it seems to charge my camper battery fine.  Glad you resolved the issue.  Thanks!  (Greg) 
    2019 [email protected] 320 S Boondock Lite; Alde Compact 3020 Boiler; 2007 Toyota Tundra TRD (5.7L V8)
    Greg & Marlene (Tucson, AZ)


  • MarcelineMarceline Posts: 473Member
    Bayliss said:
    @GibW, it seems odd that your tow vehicle lights must be "on" for it to deliver 13.7v to charge the trailer battery.  Did your dealer provide any explanation as to why that is?  I don't turn on my lights on my 2007 Toyota Tundra while towing and it seems to charge my camper battery fine.  Glad you resolved the issue.  Thanks!  (Greg) 
    My understanding is that the tow vehicle’s alternator output may be controlled by an onboard computer, and that computer will order a higher output when the vehicle’s headlights are turned on. But this may be specific to certain vehicles. 
    San Francisco Bay Area
    2013 CS-S [email protected]
    Battered but trusty 3.5l V6 Hyundai Santa Fe
  • GibWGibW Posts: 77Member
    Exactly. Many of today's autos have "smart" alternators that only produce a charge when sensors tell it that it's needed. This is intended to save fuel and enhance efficiency. This is what happens with our Kia. When the engine is running and lights are off, the charge line only shows 12.5 or 12.6 volts or the amount of charge in the vehicle's battery. But when the lights are on, the charge line shows 13.7 volts. My understanding is that many trucks do not have this feature as fuel efficiency is less of an issue but I would also guess that this may be changing especially with the new breed of mid-size pickups.
    2017 [email protected] Max-S, silver & silver, towed by a Titanium Silver 2018 Kia Sorento AWD V-6, Twin Cities MN
  • davel4wadavel4wa Posts: 74Member
    A short in a fuse holder is it's normal state, by the way. What you had was an intermittent open. Wouldn't it be nice if dealer personnel would inspire us with their knowledge and correct use of terminology. 
  • davel4wadavel4wa Posts: 74Member
    Alternators in automobiles have built in voltage regulators and have for decades. It is the job of the regulator to keep the output voltage of the alternator at the proper level by varying the exciter current in the alternator. At idle speeds it's not uncommon for the voltage to be close to the static battery voltage. As the engine speed increases or as the electrical load increases the alternator output voltage will increase to a level sufficient to keep the battery charged and supply current to the load. There is nothing special about this. What some vehicles have, particularly those equipped for towing, is a relay that controls the power supplies to the towing harness.
  • ArtArt Posts: 2Member
    Having a relay in the trailer towing circuit is the proper way to insure you will never drain the TV battery when it is not running.
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