No 12 Volt Service inside camper

[Rob in Windsor]

2013 Rockwood 8265WS 5th wheel.
I replaced the RV battery today. The 3 slides work, the front legs work, the awning and the back jacks work. But the lights inside, the water pump and who knows what else doesn't work. I have no indication on the switch(?) panel to tell me tank levels or battery level.
When I connect to shore power, everything works fine.

Please help.

[TitanMike]

The items you mentioned are often wired directly to the battery with their own inline fuses. Sounds like the battery master switch is in the off position.

If you are unsure where it's located in your 5th wheel, just follow the positive lead from the battery(s) to it''s first connection. That's usually the switch.

[Mr. Dan]

IFFF you happened to hook up the battery backwards even for a second, you blew the two reverse polarity (not ‘reversible’ as we’ve seen in this forum) fuses. This might cause the failures you’re seeing. Often those 2 fuses are on the face of the converter and are 30 or 40 amp fuses.

[Rob in Windsor]

Titan Mike,
I tried that switch in both positions and had no success in either.

Mr. Dan,
I would be embarrassed to find out that is the problem, lol. But I am hoping you are right. I took the old battery out, put the new one in, in the same position as the old, not once looking at the pos or neg.
Going to cross my fingers and look tomorrow.

[Mr. Dan]

Originally Posted by Rob in Windsor

Titan Mike,
I tried that switch in both positions and had no success in either.

Mr. Dan,
I would be embarrassed to find out that is the problem, lol. But I am hoping you are right. I took the old battery out, put the new one in, in the same position as the old, not once looking at the pos or neg.
Going to cross my fingers and look tomorrow.

I don’t keep exact figures on how often this is reported per month but it’s a familiar scenario!

[Larry-NC]

Originally Posted by Rob in Windsor

Titan Mike,
I tried that switch in both positions and had no success in either.

Mr. Dan,
I would be embarrassed to find out that is the problem, lol. But I am hoping you are right. I took the old battery out, put the new one in, in the same position as the old, not once looking at the pos or neg.
Going to cross my fingers and look tomorrow.

It might not be from an actual reverse polarity connection. I've seen those fuses blow just from hooking up a battery that's somewhat discharged while the converter was powered. A big burst of current must have flowed initially.

Larry

[Rob in Windsor]

Well, the battery is hooked up correctly and the 2- 40 amp fuses are good. I am still getting no 12 volt services when unplugged except for the legs and slides.

[TitanMike]

Originally Posted by Rob in Windsor

Well, the battery is hooked up correctly and the 2- 40 amp fuses are good. I am still getting no 12 volt services when unplugged except for the legs and slides.

You have an open circuit between the point where the leg and slide motors are connected to 12v and the converter.

Do you have 12v at the converter battery connections when unplugged? Be sure to measure at the large wires where they go into the converter. If not you have a break in the positive wire, a ground to the frame disconnected at the converter end, or you haven't found the hidden circuit breaker between converter and battery yet. Or an unnoticed shutoff switch.

[Rob in Windsor]

I will check those tomorrow. Thanks for the help. Will keep in touch.

How likely are those battery cutoff switches to crap out?

[Larry-NC]

Originally Posted by TitanMike

You have an open circuit between the point where the leg and slide motors are connected to 12v and the converter.

Do you have 12v at the converter battery connections when unplugged? Be sure to measure at the large wires where they go into the converter. If not you have a break in the positive wire, a ground to the frame disconnected at the converter end, or you haven't found the hidden circuit breaker between converter and battery yet. Or an unnoticed shutoff switch.

The hidden circuit breaker is often under the trailer. near the batteries. You have to crawl under the trailer. It looks like this. Push the button on the end to reset it.

Larry

[Cypressloser]

Visually inspect the cable lugs on the battery terminals, make sure they are in good shape, not loose and make good contact. Next, with a multimeter measure the voltage starting at the battery and do the same at the converter where the 12 leads enter the panel, go through the reversed polarity fuses - the whole nine yards. If you do get power at the panel, observe the voltage difference between the battery and the panel, more than 0.2 or 0.3 Volt drop can indicate a poor connection or broken wire. You could also test each cable individually for continuity. This may give you a clue and point you in the direction where the problem is. If you do have a battery disconnect switch, test it for continuity too, you never know.

Please do all this with the shore power disconnected for safety and to prevent false readings!!!

[Larry-NC]

Originally Posted by Cypressloser

Visually inspect the cable lugs on the battery terminals, make sure they are in good shape, not loose and make good contact. Next, with a multimeter measure the voltage starting at the battery and do the same at the converter where the 12 leads enter the panel, go through the reversed polarity fuses - the whole nine yards. If you do get power at the panel, observe the voltage difference between the battery and the panel, more than 0.2 or 0.3 Volt drop can indicate a poor connection or broken wire. You could also test each cable individually for continuity. This may give you a clue and point you in the direction where the problem is. If you do have a battery disconnect switch, test it for continuity too, you never know.

Please do all this with the shore power disconnected for safety and to prevent false readings!!!

Tarnish on the connecting lugs at the battery can be deceiving. The lugs can look clean (no white or blue-green fuzz) but be non-conducting due to a very thin film. Think slightly brown penny instead of bright pink-gold. This tarnish is tough. Tightening the wingnuts down won't break it. It won't easily brush off or sand off. I've had to chip/scrape it off with a utility knife.

In our Cherokee 38P, the positive wire from the battery goes right to the distribution board (fuses and feed from the converter). The negative wire goes to a ground point on the frame, under the trailer. Another negative wire goes from a different ground point on the frame to the distribution board. There's no particular reason why they did it that way. The batteries are only about four feet from the distribution board. But it was two other points for me to clean when solving a problem I had.

Larry

[Rob in Windsor]

Larry,
I have reset those 2 breakers near the battery.
Could there be another somewhere else?

[Larry-NC]

Originally Posted by Rob in Windsor

Larry,
I have reset those 2 breakers near the battery.
Could there be another somewhere else?

Hard to say, Rob. Every trailer is different in this regard. But it seems unlikely.

Maybe try a systematic approach.

1. Measure voltage across the battery. When you take this measurement, take it by probing the terminal lugs on the cable. Do you see 11.5-12.5 volts? If not, go to step 2. If so, go to step 3.
2. Now measure the voltage by probing directly onto the battery terminals. If you have 12 volts, the terminal lugs are tarnished. Clean them really well. If not, battery is low. If so, reconnect the battery and proceed to step 3.
3. In the converter/fuse box, there are two units. One is the big circuit board with fans; that's the power supply. The other is a 3" x 5" card with fuses and LEDs. That's the distribution board. At the distribution board you should see two white wires (negative from converter power and negative from battery or ground) and two red (maybe black) wires (positive from power supply and positive from battery) coming in. (The two negatives are probably connected together.) At the distribution board, measure the voltage between positive from battery and negative from battery. If you can't figure out which positive is which, make two measurements). If you get some flakey voltage, turn on a light or two. (If no load is connected, you can get misleading stray voltage measurements.) If you have 12 volts here, there is likely to be a bad ground. Go to step 5. If you do not have 12 volts here, it could be a bad ground or a bad connection on the positive wire. Go to step 4
4. Follow the positive (red, maybe black) cable back from the battery. Underneath the trailer, usually near the tongue, you will find the circuit breaker we discussed. You should have 12 volts between each terminal and a clean ground spot anywhere on the frame. If 12 volts is present on the battery end but not the other end, try resetting the breaker. If it won't reset, try cleaning both terminals. If you still only have 12 volts on one end, the breaker is defective. If you have 12 volts to ground, on both ends, go to step 5.
5. Bad grounds can plague you, because they can be anywhere. Disconnect the white wire at the battery negative terminal. Follow the white wire back from the battery. Does it terminate on the frame? It looks like the illustration. it apart, clean with a wire brush or sandpaper, and reassemble. The external-tooth star washer MUST go between the lug and the frame. Now, if the white wire terminates on the frame, the white wire from the distribution board must also terminate on the frame, likely somewhere else. Figure out where the white wire from the distribution board goes through the trailer floor and follow it to a different ground connection. Clean and reassemble that connection in the same way. Reconnect the battery and test again.

Let us know how this comes out.

Larry

[cavie]

Turn off the converter. Start at the battery with a multimeter. Turn off the battery switch. Check voltage at the battery. Follow the wire to the next connection wherever it is. Check the voltage. If it's the battery switch. Turn it on. Check the voltage. Follow the wire to the next connection and so forth until you get to the converter. If you have 12 volts at the converter turn it on. If you still have no voltage your RP fuses are bad. The convert is working because you have 12 volts on shore power. If you have 12 volts at the converter connections and the two 40 amp fuses are good then you have an internal converter problem.

[Rob in Windsor]

Cavie and Larry,,,,
Today I did what you both suggested. All in all, I found 2 grounding points. One near the battery and the other on the frame below the converter. I cleaned them both up and still nothing.
With the trailer plugged into the house, I have 12 volts at the DC portion of converter.
With the trailer unplugged and on battery, all of the checks I made proved correct until I reached the converter. Still 0 volts. So the battery cut out switch, re settable relays, all proved fine.
I opened a good portion of the underbelly paneling but found nothing else.
So frustrated. But it won't keep me from camping this weekend.

[Larry-NC]

Originally Posted by Rob in Windsor

Cavie and Larry,,,,
Today I did what you both suggested. All in all, I found 2 grounding points. One near the battery and the other on the frame below the converter. I cleaned them both up and still nothing.
With the trailer plugged into the house, I have 12 volts at the DC portion of converter.
With the trailer unplugged and on battery, all of the checks I made proved correct until I reached the converter. Still 0 volts. So the battery cut out switch, re settable relays, all proved fine.
I opened a good portion of the underbelly paneling but found nothing else.
So frustrated. But it won't keep me from camping this weekend.

Rob,

Before we start, let's check some things we should have asked earlier.

• At the distribution board, there are two terminals where heavy wires come back from the battery, They will be clamped down by heavy screws, either Allen head or slotted. Make sure those are really tight.
• Check the two 30 (or 40) amp fuses on the distribution board again. Pull them, If your multimeter has an ohms scale, make sure they are 1 ohm or less, not "1." which stands for infinity.
• Might also check the battery and make sure it's still around 12 volts. Be sure to change the multimeter back to 20 vDC before measuring.
• I know we asked this, but are you sure there's no battery-disconnect switch or disconnected wire?

The battery has 12v, but it doesn't show up at the converter terminals.

Path for the positive side is either battery-to-circuit-breaker-to-converter. To test the positive side, let's take some measurements from positive to the trailer frame. We'll assume the negative side is good.

1. Measure voltage from the 12v battery post to trailer frame ground. (May have to press ground probe hard to break through the paint.)
2. If you get 12v there, follow the positive cable to it's termination, probably the under-frame breaker.
3. Measure between the breaker terminal (the one connected to the battery) and frame ground. Should be 12v (This tests the first cable.).
4. Now measure from the other breaker terminal to ground. Should be 12v. (This tests that the breaker is reset and good.)
5. Now go to the distribution board. It has two positive wires coming in, one from the battery and one from the power supply. Since shore power is disconnected, there won't be any voltage on the one from the power supply. We need to measure from the battery terminal (the other one) to ground. There's usually no frame ground accessible inside. Can you take an automotive jumper cable, connect one end to the frame (e.g., metal steps into trailer) and put the other end on the floor near the converter? Measure from the positive terminal at the distribution board to the jumper cable. Should be 12v.

It all of these tests pass, we have proved two things.
The entire positive path is good.
The negative path from battery to ground is good.
The only thing we haven't tested is negative path from converter to ground.
Let us know how these tests do, and then we'll write about testing the negative side.

One final question, Rob in Windsor: Which Windsor, Illinois or Virginia, or some other one?

Larry

[SamR]

Rob I had the same problem on my 2013 Rockwood 8289ws. I replaced the battery, checked every fuse, breaker, wires, etc and nothing.
There is a junction box underneath the king pin where all the wires tie in for the umbilical cord. There also is an external ground strap attached to the box and the frame. When I took the cover off the box this ground strap fell to the ground. Reattached with a bolt to the junction box & tightly to the frame & bingo everything works!
Hope this solves your problem as well!

[Rob in Windsor]

My 12 Volt dilemma has been solved. I read Sam's reply and figured why not, it's one more thing to check that hasn't been looked at yet. I located the junction box behind the kingpin and sitting beside the box is a re-settable breaker thing. You guessed it, the thing had tripped.

I want to thank everyone for their suggestions and help through this past week. There is truly a wealth of knowledge in this forum. Happy camping to you all.