I'm Afraid to Ask

[juel]

Please bear in mind that "I know nothing" when you answer my question. I have a 78 24ft Argosy that I am restoring. When I went to put up the new 12V lights half of them wouldn't come on. I found a blown fuse in the 12V panel. I have the Univolt and a brand new battery in place. When I replaced the fuse none of the lights would come on. I plugged the trailer in to the household current and then all the lights came on. I wonder if there is a short somewhere that didn't blow a fuse but drained the battery. I thought I might have left something on; however, I am in the trailer a lot and I know no lights were left on. I could hear the water pump if it was on, so I'm kind of at a loss. I have read the posts on the forum from all of you who know so much about electricity and I want to say that I understood very little. If you could just give me a starting place and the equipment I might need to find this problem I would be very grateful. When I put the battery in last week, the lights worked without the Univolt being plugged in. What am I dealing with here? Judy

[overlander63]

Originally Posted by juel

Please bear in mind that "I know nothing" when you answer my question. I have a 78 24ft Argosy that I am restoring. When I went to put up the new 12V lights half of them wouldn't come on. I found a blown fuse in the 12V panel. I have the Univolt and a brand new battery in place. When I replaced the fuse none of the lights would come on. I plugged the trailer in to the household current and then all the lights came on. I wonder if there is a short somewhere that didn't blow a fuse but drained the battery. I thought I might have left something on; however, I am in the trailer a lot and I know no lights were left on. I could hear the water pump if it was on, so I'm kind of at a loss. I have read the posts on the forum from all of you who know so much about electricity and I want to say that I understood very little. If you could just give me a starting place and the equipment I might need to find this problem I would be very grateful. When I put the battery in last week, the lights worked without the Univolt being plugged in. What am I dealing with here? Judy

Judy, you may have two problems combining to make one mess. First, did any of the lights come on immediately before you replaced the fuse? Did you try taking that fuse out, and unplugging the trailer, to see if any lights came back on?
Some previous owners were sneaky about hooking stuff up to the battery you wouldn't think to look for, because the trailer never had it to begin with.
Check any outside (and inside) storage compartments, to see if there are any lights you don't know about, and that shouldn't be there, that are on. Next, check to see if the previous owner replaced the stock two way (LP & 110v) refrigerator with a 3 way (LP, 110v, AND 12vDC) fridge. Check to see if the breakaway switch for the trailer brakes has been actuated. If so, it will drain the batteries in short order. Check to see if you have a propane or carbon monoxide detector, if so, unhook them, they will drain your batteries. If you have a test light, get it. Hook the clamp end of the test light on the negative battery post, and the other end of the test light on the battery cable end. The light should not light. If it does, you have a draw. If it lights, go to the next step. The next step will require an able assistant. While the light is still hooked up as described, have the assistant unhook each of the 3 house fuses, one at a time. If the light goes out when the assistant removes a fuse, that is the circuit where the draw is. Now, the Univolt. The Univolt should not drain the battery when the trailer is plugged in, but I have seen stranger stuff. If you still have a light on the test light, after removing the other 3 fuses, remove the 50 amp fuse for the Univolt, if the light goes out, you have a Univolt problem, if it is STILL on, unhook the fuse that says "tow Vehicle", that is the absolute last fuse for your system, if the test light is still lit after all this, you have a direct draw or short between the positive terminal of the battery and the trailer. If this gets too confusing, and it might, PM me, and I will try to talk you through it.

[SafeHarbor]

Hi, Judy,

Do I read that correctly that ALL lights work when you plug in the trailer? I think a logical thing to do first would be to check the charge on the battery, but you'll need somebody with a multi-meter who knows how to use it. (It's not hard.)

The Univolt is designed to charge the battery as it powers the 12 volt DC system. My 75 Argosy 28 has a big fuse mounted on the wall near the battery box. Have you looked to see if that fuse is intact? Look at it with a flashlight -- it'll be obvious if its blown.

I think you may need to remove the battery and charge it with a home charger before you can really get into troubleshooting this.

Lamar

[john hd]

When I replaced the fuse none of the lights would come on.

did you replace the blown fuse with another blown one?

sounds dumb but it happens, i've seen bad fuses new right out of the box!

john

[overlander63]

Originally Posted by overlander63

First, did any of the lights come on immediately before you replaced the fuse? Did you try taking that fuse out, and unplugging the trailer, to see if any lights came back on.

John, that was somewhere in the information overload I gave her.

[driftwood]

If you could just give me a starting place and the equipment I might need to find this problem

Judy,

If your going to get into this stuff you need some kind of test equipment, like you requested. I am not the biggest fan of Radio Shack, but there must be one near you.

This is a cheap but useful tool for most of your needs. The instructions are simple.

15-Range Digital Multimeter
$19.99 Brand: RadioShack
Catalog #: 22-810 Model: 22-810

As you encounter various problems to determine their cause, I am confident that many in the Forum will direct you as to its use.

One of these and you can start giving john hd competition!

[juel]

Thanks for all your very simple advise. As soon as it stops raining and I have another week-end, I'll start looking for the problem. I did try the lights before the new fuse and after. Only half of them worked before the blown fuse, then none of them worked after I replaced it. BUT before the battery was new and evidently had a charge because the Univolt was not plugged in. I've unplugged the trailer for now. I will tell you that there was a little orange, round light by the refrig that you turned this little round switch and the little round light glowed orange. I couldn't find that it was connected to anything, although the red wire ran out to the outside refrig compartment and ended there. Needless to say, I took it out because it ran across the floor and we are putting in wood floors which wouldn't go over this large a wire. The PO said he thought it was for a fan to help keep the refrig cooler in the desert but the fan was no longer there. Now I'm wondering if I've made a mistake in disconnecting that. Who knows? I thank you all and I will keep you posted on my progress, when I get time to make any that is.

[juel]

Guess what. Unplugged the Argosy and went out this morning and ALL the lights are working. I'm confused. Judy

[overlander63]

Originally Posted by juel

Guess what. Unplugged the Argosy and went out this morning and ALL the lights are working. I'm confused. Judy

Check to make sure the + and - terminals are connected to the correct post on the battery. If the terminals are reversed, it can cause all kinds of mischief. Like, for example, blowing fuses, and the lights going off when you plug the trailer into AC, as you are creating a 40 amp or so draw on the battery, if not a direct short.

[Bob Thompson]

I had a similar problem on an SOB trailer. It turned out there was a circuit breaker located along the hot lead between the battery and the 12 volt fuse panel. It will be an in-line circuit breaker usually located about 36" from the battery. It can be reset by pressing in the button on the circuit breaker. Hope this helps.

[FrenchBern]

Judy, I think I know what your problem is if your argosy is connected through the fuse panel in the Univolt as in my 1970 Overlander. The 12 volt buss is supplied by 3 different sources namely #1 the trailer battery through wire d and a fuse labeled m, #2 the car battery through wire a and another fuse labeled m and finally #3 the Univolt if the input is connected to 120 volts AC. If I interpreted what you said right, the lights work when connected the 120v ac and with the tow vehicle connected. That would mean the fuse to the trailer battery is open or the wire is bad or not connected between that fuse and the battery. If your problem is not fix already I will be glad to provide additional information.