Old camper wiring

OK got my new electronic troubleshooting toy in the mail yesterday (tone generator and probe). I traced the 3rd wire and it is connected to the tow vehicle plug harness (7pin). A quick continuity check with my trusty D'Arsonval meter confirmed it.

I did have in line fuses installed in the wire coming from the converter. They looked cheesy. Newer style automotive push in fuses. I'm replacing both one at front exposed to elements, the other in the converter compartment.

Yes the little break away brake box has a wire coming from it. I haven't traced it yet. I plan on replacing the broken cable too. For now the trailer brakes are working.

Thats great idea to check for leaks with positive air pressure! You guys n gals are full of great ideas!! Keep em coming!

Thank you
RK

Roy B has some excellent advice there.
One way to check the converter/charger in the trailer is to first measure voltage across the battery posts. Plug into shore power and measure again. If the battery is fully charged, you should have somewhere around 12.7 V. When the converter/charger is powered through the shore cord, you should have around 13.6 V or so. (This assumes you have a '86 converter that is single charging stage).

If you don't have 12 V power when disconnected from shore power, check for a blown fuse or failed circuit breaker close to the battery. It may be tucked up under the tongue or frame. May even be inside a junction box but an '86, probably is exposed and connected to your (+) phase battery cable. This is a common failure point.

One of the wires removed from the distribution post may have been for the emergency break away brakes or an alarm/disconnect. Often, they are wired separately.

If you did a bunch of sealing and work to get any possible water leaks fixed, you may want to do a blower pressure test to find any pinholes or leaks that remain. I did 6 mos. of work on my old rig, removing and spreading all manner of good quality caulks to insure I had no leaks. A pressure test turned up about 20 on the first test. I ended up putting Eternabond tape around everything on the roof and filled the siding leaks with Geocel 2300, a polymer sealer. I test every year but have no leaks. I use a furnace blower but other guys have used a rug drier or even a leaf blower.

Good luck with your new hunting camp. Put some pictures up if you get some time.

Thinking more, the wire from the converter should pass through a fuse or circuit breaker near the tongue of the trailer. At this point on some rigs, the power from the TV connects to the wire from the battery.

Did you find a wire going to the trailer break away switch?

Ahhh thanks for the many replies fellas!

I did not consider the tow vehilcle charge conn.

Bought new deep cycle battery and solar charger along with solar controller. This camper is used and parked at the hunting lease year 'round. We do not visit there during the summer but once every two months or so. We have shore power there but shut it off during absences to keep power bill down.

The trailer has an emergency separation cable connected to a box but the cable is broken. The trailer is not used for towing very much and once I get it back there and parked/setup I imagine it will stay there a long while.

I own a '05 KZ toy hauler that stays at the house in the event we go "camping" some where.

I towed the old girl home for some major upgrades. I replaced the roof a/c as it no longer worked. Re-applied the rubber coating paint over the metal roof due to thin spots showing thru. Replaced both vents due to cracking and leaking. Replaced the bath fan bc all the orig blades were missing. Rebuilt the missing bench from scratch bc wanted to restore orig design kitchen table/bed. The Orig owner tore it out and was using a chinchy fold out card table that was junk.
Pressure washed years of green mold and black gunk off the outside. Discovered a lions head design on the front shade that was so black you couldnt see it.

Repacking and checking the wheel bearings is next.

The older trailer get wired up by the users and who knows what colors they end up using.... You need to just trace them out and see where they go...

The RV TRAILER world colors are any thing that is colored including BLACK will be hot +12VDC POSITIVE like house wiring is... SOLID WHITE will always be -12VDC NEGATIVE. WHITE with color stripes will be POSITIVE +12VDC wiring..

Of course the AUTOMOTIVE WORLD uses the RED cables and also many other colors but BLACK is ALWAYS GROUND (-12vdc NEGATIVE)... When you go buy a new JENSEN CAR RADIO to install it comes roght out of the ox with RED wire to go to +12VDC and BLACK WIRE to go to -12VDC frame ground. Right away you find yourself installing a RED WIRE on top of a BLACK wire haha... Makes us old guys turn over in our graves...

These get all mixed together especially with the older trailers...

Here is block diagram showing many of the systems that need the 12VDC so maybe this will give some idea what might be powered up by the 12VDC systems



About the only clues you get is the HEAVY GAUGE wiring is most always charging cables... The smaller guage wiring will most likely be going to a single low power consumption device of some sort... Most things direct connected to the battery terminals would be the tongue jack, the emergency BRAKES operation, the 12VDC coming from the tow vehicle, etc... The heavy gauge wiring comes from the converter/charger unit which also feeds the same point on the 12VDC FUSE PANELS...

People will get into big troouble when they change out their batteries and don't remember where all the cable went to. I always look on the battery cse and find out which terminal is POSITIVE nad which is NEGATIVE. Then I make sure the wiring from the NEGATIVE terminals goes directly to the frame ground. If any wire has a in-line fuse in it you will know that it will go to the positive terminals. You have already found out you can't just go by wire colors as both RV TRAILER and AUTOMOTIVE worlds color schemes seem to get mixed together

Spend some time and hand trace them out. If the get reversed then the REVERSE POLARITY fuses will blow on you in addition to some of the IN-LINE fuses between the Battery terminals and the CONVERTER/CHARGER unit. Once you get everything all wired up correctly and good to go then use your cell phone camera to take some pictures of it and carry the pictures inside the trailer to show where all the wires go to... Being OLD SCHOOL here I have my POSITIVE wires all marked with RED fingernail polish...

Of course if the battery has no fluids in it then it is shot and must be replaced...

Also be aware you must have a good battery engaged when you tow your trailer over DOT ROADWAYS as the emergency BRAKE operation is controlled by the on-board working battery in the event the towed trailer becomes disconnected when being towed. This is a DOT Safety law which can be enforced. It is also a safety feature to keep damage to a minimum to other trailers on the roadways...

I'm sure your insurance will not go in your favor if no battery was found connected or working if this happens to you...

Not to be taken lightly...

Roy Ken

Welcome to the forum. I suspect the wire in question is either a charge line from the tow vehicle or a direct line to a DC plug inside the trailer. My rig has a direct line plug for television I suspect.

Probably the charge wire from the tow vehicle to the battery. This allows the camper battery to be charged by the alternator in your tow vehicle while driving.

See if you can trace it down. It should go to the junction box where the large black cable that plugs into your tow vehicle goes to.