12v question no power from battery

[386kustoms]

i think this trailer is never ending lol. just when i think i am on the last step a new problem rises up. ive got a 77 argosy minuet. it has a new lota power converter installed in it. when i am on shore power plugged in everything works perfect on the inside all 110 and 12 v. now we are taking our first major trip in her next month so i decided to get a battery for the trailer. i took a spare car battery i had laying around just to make sure everything is in working order. well i hooked it all up and non of the 12v works on the inside. now i traced everything and i can always find 12.52 volts leading everywhere. has the 12.5 volts going to fuses and going to converter. but nothing works on the inside. once i plug 110 back up everything is fine. also i decided to hook up my tow vehicle and with that all hooked up none of the interior 12v works at all. i have running lights and everything outside is working but i cant get any interior lights to work. and one last thing is when the tv is running the battery is not charging. it stays at a constant 12.5

so to try to explain easier if i boondock the night at a walmart parking lot i cant get any lights to work on the inside

any ideas ????

[TG Twinkie]

Sounds like you either have a bad/dead battery or it is not wired up correctly. When you are on shore power the converter is providing the 12 volt power. That's why it works when you are plugged in.
It doesn't sound like the battery is charging, if it is a good one. Look for a fuse in the negative side wiring from the battery to the place where it (the wire) connects to the frame. It will be a glass fuse, 30 to 50 amp. Also check the fuse holder to make sure it is making good contact with the fuse and wires going in and out.

[386kustoms]

Originally Posted by TG Twinkie

Sounds like you either have a bad/dead battery or it is not wired up correctly. When you are on shore power the converter is providing the 12 volt power. That's why it works when you are plugged in.
It doesn't sound like the battery is charging, if it is a good one. Look for a fuse in the negative side wiring from the battery to the place where it (the wire) connects to the frame. It will be a glass fuse, 30 to 50 amp. Also check the fuse holder to make sure it is making good contact with the fuse and wires going in and out.

yes i have checked all the fuses, infact like i said i am running a meter and i am getting 12.5 volts to the fuses and past.

as far as the vehicle not charging i am doing some research on that now. it seems like my tv ( 2003 silverado) center pin is for reverse lights, i am guessing that i have to rewire the center pin on the truck to the 12v positive of the battery w a 40 amp circuit breaker in the line.

[Wazbro]

Originally Posted by 386kustoms

yes i have checked all the fuses, infact like i said i am running a meter and i am getting 12.5 volts to the fuses and past.

as far as the vehicle not charging i am doing some research on that now. it seems like my tv ( 2003 silverado) center pin is for reverse lights, i am guessing that i have to rewire the center pin on the truck to the 12v positive of the battery w a 40 amp circuit breaker in the line.

No do not wire 12V hot to the center connector the 12V is one of the pins around the outside of the 7-pin plug. You may have to add a fuse to the under hood fuse box, Silverados often came with a dummy fuse installed for the 12V trailer feed, sometimes for the brake controller to.

In your trailer there may be a battery shutoff switch, check and make sure it is on.

[386kustoms]

Originally Posted by Wazbro

No do not wire 12V hot to the center connector the 12V is one of the pins around the outside of the 7-pin plug. You may have to add a fuse to the under hood fuse box, Silverados often came with a dummy fuse installed for the 12V trailer feed, sometimes for the brake controller to.

In your trailer there may be a battery shutoff switch, check and make sure it is on.

ok im going to go check the fuses right now. also i have not ordered my brake controller yet. i am getting it tue. why in the wire diagram for my argosy does it show that the center pin is the blue wire witch is the charge line?

[386kustoms]

also now this is really weird. i had the battery in the trailer hooked up. keep in mind it is a car battery. it showed 12.5 volts at the fuse panel, my wife flipped the outside light on and it came on. i was like WTF but it went out after about 3 seconds. she kept flipping the switch but it never came on again.. now the weird part i had my multi meter hooked up and it showed 12.5 volts but when she flipped the switch it dropped right down to .8 volts and then back up to 12.5 when she turned the switch off. could it be that it is a wrong battery? do i need a specific battery for the trailer?

[richinny]

are the + & - cables correct on the battery?

[TG Twinkie]

If the battery you have is a good battery, even though it's a car battery, it should work.
From what you just described it sounds like you have a bad connection. At the battery or maybe at the ground / common connection to the trailer.
You can get on the Internet and look up the wiring layout for the 7 pin trailer plug. Don't rewire your truck. The old trailers were not wired the same and you will have to rewire the 7 pin plug to get it to work. As mentioned above, your truck may have a dummy fuse. You should get the wiring straighten out before using the brake controller. Chances are good that it won't work either. If I can be of any help, PM me.

[386kustoms]

well the red is to pos and black to neg. so im assuming it is hooked up correctly.

[TG Twinkie]

Here is the pinout for the 7 pin UCord. (Trailer Plug) If you rewire the plug on the trailer to match this, it will work on your truck. The wire colors on the trailer may not match what is on here, so check out each function, ie tail lights, turn signals etc. before connecting them. If you need help on how to ID each wire on your trailer, let us know.

Pictures by dougbowman88 - Photobucket

[386kustoms]

ok so i have a dummy fuse in the stud 1 fuse area. i will get a new fuse 40 amp for that . after that is done i guess i need to wire my 7 pin connector on the trailer itself to match this?

How To Connect Auxillary Power On 2008 Chevrolet Silverado 2500 To Charge Trailer Breakaway Battery | etrailer.com

[386kustoms]

Originally Posted by TG Twinkie

Here is the pinout for the 7 pin UCord. (Trailer Plug) If you rewire the plug on the trailer to match this, it will work on your truck. The wire colors on the trailer may not match what is on here, so check out each function, ie tail lights, turn signals etc. before connecting them. If you need help on how to ID each wire on your trailer, let us know.

Pictures by dougbowman88 - Photobucket

lol i guess we typed that same link to the same pic at the same time. lol. well thats good i understand all that, im still curious why i cant get 12v to work off the battery. where is the common ground to the trailer located? in my setup the neg from the battery goes to a fuse. from that fuse it goes to a connector that splices out to the univolt and the harness. after that i can not trace the wires anymore cause they go into the trailer itself. i dont think the univolt has anything to do with this correct?

[TG Twinkie]

Where are you reading the 12.5 volts? The negative side of the battery should connect to the skin or frame of the trailer. The positive should go into the Univolt, if it is a Univolt. Somewhere between where you have your meter connected and the battery you have a bad connection causing the voltage to drop to the .8 you are reading. Trace out the wiring and check every connection. In my Argosy the common/ground connection to the skin is in the closet in the bath and it has a 50 amp fuse between the wall connection and the battery.

[TG Twinkie]

In re reading your OP I see you have a modern converter.
Sometimes these glass fuses cook themselves and while they read good with a meter, they are bad.
If you have a piece of wire or a jumper, turn on one of the ceiling lights in the trailer, then put the jumper across the fuse in the negative side and see if the light comes on.
The two wires off of the battery should eventually be connected to the converter in some way shape or form. The positive wire from the battery and the converter should connect to the fuse block or panel. The negative wire from the battery should connect to the negative terminal of the battery and to the negative terminal of the converter as well as to a point called the common/ground buss where all of the white wires come together. Is the fuse panel new? Or is it the original?

[Splitrock]

It reads like there are three issues:

1. The interior 12 volt power,

2. The 7-way towing connection, and . . .

3. The charge line backfeeding the breakaway brake switch.

The coach battery neutral is fused on my trailer as well. I remove all fuses for multi-meter testing until I find a solution.


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[386kustoms]

well that was interesting, it ended up being one of the original glass fuses. it kept the 12.5 volts until a switch was turned on then it wouldn't keep the voltage. ive never seen anything like that. i just couldn't find it b4 because i couldn't watch my meter while i turned something on. atlest that is taken care off.

now tomorow i will get the corect 40 amp fuse for my truck where teh dummy fuse is. now my parking lights and brake/signals work fine so i guess i will have to just rewire the blue wire on the trailer to match the pin conector on my truck

[trydigital]

sorry wrong thred

[TG Twinkie]

Sometime in the future you may want to consider upgrading the fuse panel. Trust me. This problem will happen again with those old glass fuses.
Don't forget the charge line and brake wires. Glad you are up and running. Travel Safe and Keep the Shiny Side UP!