50 Amp auto reset breaker

[VTSweetpea]

I'm trying to physically locate the 50 amp auto reset breaker that is between my coach batteries and the low voltage disconnect behind my driver seat.
The wiring diagram for my 2001 Concourse shows it and a 15 amp auto reset breaker between the batteries and the LVD. The 15 amp breaker is right next to the LVD. But the 50 amp breaker is no where in sight. Is it located behind the cloth covered pillar the LVD is mounted to?
I need this info to trouble shoot an issue with my Progressive Dynamics PD 4645 converter charger. PD tech support seems to think that this breaker might be the cause of my issue. BTW- the issue is the charger ( on shore power ) is putting out 13.4 volts but I'm only seeing 12.3 at the batteries.

[Jlfchinook]

I believe it is located under the coach and then feeds into LVD, seems I remember it is inside a shield or box below where the LVD is located, but outside next to battery compartment.

[chin_k]

Yes, it is the famous white plastic box with holes that everyone wonder what it is.

I don't know how hot it is for you, but I would troubleshooting inside the rig first. You need to tell us how you measure your voltage, and find out where is the voltage drop from the converter->LVD->breaker->batteries. Use the same grounding point as you move the positive probe from one point to another until you find the weakest link.

[VTSweetpea]

Thanks to all that responded about the location. It is indeed the white mystery box located under the coach. I've looked at that thing a hundred times and always wondered what was under it. I have received several suggestions as to trouble shooting steps. Will try them tomorrow and report back.
Thank you all again.

[BobW9]

The 50 amp resettable fuse is inside this white plastic box, under the chassis between the driver's door and the battery compartment. This photo is looking up, you can see the 2 fresh water drain tubes to the right, and the white box on the left, with 2 cables in conduit going into it. One is coming through from the battery compartment (the dark fiberglass wall on the right side where the red and other cables go) and the other going up to the LVD inside the coach.

In spite of it being covered, my fuse was all corroded up, so I had replaced it. Though since then I've moved my batteries inside and no longer use it at all.

[VTSweetpea]

UPDATE- Took white cover off of auto reset fuses. They both are heavily corroded which I guess is to be expected given their location and the fact that they are 20 years old. (crappy pic attached) I could get no stable readings off them with my meter. Jumped all over the scale. Regardless, I've already ordered replacements. May not be the source of my problem, but I'll feel better with new ones installed.

[chin_k]

The rust is what make the meter reading going all over the place. You need to find the terminal down to bare metal if you want to have a good reading. They are cheap, and easy to replace, so it is always good to do that consider how corroded they are right now.

Here is my suggestions:
1, clean the wire's terminal since the rust will give you sub-optimal conductivity even when you put brand new breakers on there.
2, after you clean the wire terminal, go back to troubleshooting! You can't leave us hanging like this! Did you measure the voltage at the LVD V-out to make sure you don't see the voltage drop there? It is very rare, but it is a good spot to figure out if it is the breakers or the grounding that is the problem.

[VTSweetpea]

I measured the voltage at Vin and Vout. It was 12.3 v at both. The way I did it was to clamp my meter ground wire to the white wire terminal on the LVD which the wiring diagram says is ground. I then touched the meter probe to the Vin and Vout terminals and took the readings. Coach was plugged into shore power and battery switch was NOT in Storage position.
If I did this wrong please tell me.
I do intend to clean the wires and terminals when I install the new breakers. Also will coat them with antioxidant grease and I ordered covers for them as well. So between that and the white box, they should be pretty well protected.
The breakers are due to be delivered next week. I will post an update when I get them installed.

[chin_k]

You are not doing anything wrong, just part of the troubleshooting. Now move the negative probe from the LVD to the DC panel where you measured the 13.4 V negative post while keeping the positive probe on either V-in and V-out on the LVD. Do you see 13.4V or you still only see 12.3? If you see 13.4 that way (more likely), then it is poor grounding from the LVD white wire. If you still see 12.3V, I'll be scratching my head a bit more.

[caconcourse]

I measured the voltage at Vin and Vout. It was 12.3 v at both. The way I did it was to clamp my meter ground wire to the white wire terminal on the LVD which the wiring diagram says is ground. I then touched the meter probe to the Vin and Vout terminals and took the readings. Coach was plugged into shore power and battery switch was NOT in Storage position.
If I did this wrong please tell me.
I do intend to clean the wires and terminals when I install the new breakers. Also will coat them with antioxidant grease and I ordered covers for them as well. So between that and the white box, they should be pretty well protected.
The breakers are due to be delivered next week. I will post an update when I get them installed.

I would try it one more time where the switch IS in the Storage position. Then look for a different voltage on Vout vs Vin on the LVD. In the storage mode, the LVD disconnect is open, so Vout and Vin should not be connected. Vout should be the voltage from the PD4645, and Vin should be the voltage from the batteries.