This is almost too embarrassing to post, but I need help in hopes of salvaging our weekend trip. I replaced the trailer-side 7-pin connector on my TT today without disconnecting from shore power, unplugging or turning anything off or otherwise taking any precautions. Long story short - in the process of that I shorted the 7 wires together as I was feeding them through a rubber boot on the new connector. Now, none of the 12V items or outlets in the trailer work. Also, the A/C does not come on (the breaker is in the on position). The breaker to the microwave was turned off at the time I shorted the connector wires, and when I flip it to the on position, the microwave works. The 110 outlets in the trailer are live. At the electrical panel, on the 12V side, none of the fuses are blown, including the two large ones. None of the 110 breakers are tripped. None of the three fuses on the PD9180 charger are blown. The large fuse in the cable between my battery bank and the PD9180 is not blown. (Oddly, after I pulled and replaced the fuses in the charger, the pendant began blinking rapidly, even though it has been plugged in and charging for a couple of weeks - I don't know if that is relevant to diagnosing the problem or not.) I'll be very grateful to hear any suggestions on what I should check. I have a multimeter. Thanks in advance.

Sometimes there is a hidden in line tiny breaker on the 12v system with a small button to push. Does not look like a breaker.It is possible the AC does not come on because the thermostat needs 12v from the furnace, but the 12v system is down.Just as a starting point what is the voltage at the battery, and at the 12v output of the converter?Jim

Are you checking these fuses with a meter? A good visual inspection does not necessarily mean a good fuse. I've been burnt by that in the past.

Jim, thanks for replying. Your comment about the inline fuse reminded me of one I'd seen. I just looked again. It's a grey plastic box, maybe 1 1/2" by 1/2" x 1/2" with two poles, it says "SHORTSTOP 12/24V K36 30A", but there is not a button on it to push. I'll be back with those voltages. Thanks.

I was only doing visuals on the fuses. I will go out and check continuity on those. Thanks, mena661.

tom496 wrote:Jim, thanks for replying. Your comment about the inline fuse reminded me of one I'd seen. I just looked again. It's a grey plastic box, maybe 1 1/2" by 1/2" x 1/2" with two poles, it says "SHORTSTOP 12/24V K36 30A", but there is not a button on it to push. I'll be back with those voltages. Thanks.Sounds like that kind of sneaky breaker with a hidden tiny button everyone gets bitten by. If there is no obvious way to reset it (some are self resetting)' check the voltage at each pole relative to ground and from pole to pole (on the off chance that somehow the ground connection opened up).Jim

Urgently Need Help Diagnosing Dead Electrical System

30 Replies

rrupert
Explorer
Jun 07, 2013
I hope you are checking things with the shore power disconnected.
tom496
Explorer
Jun 07, 2013
There is continuity across the "shortstop" fuse.

I am getting 13.42V at the posts in the electrical panel where the cables from the converter are connected. I will try to post a photo.
HiTech
Explorer
Jun 07, 2013
So the converter is working, and is connected to the battery. That's a good start. Do you have the same voltage from the battery + to the frame?

Jim
tom496
Explorer
Jun 07, 2013
I'm reading 13.42V at the converter and at the battery. The converter pendant is still in rapid blink mode.

I checked continuity of the two main 30 amp fuses in the panel, plus a couple of the ones on the individual circuits, and they are good.

I'm going to go check the shortstop fuse now.
aruba5er
Explorer
Jun 07, 2013
Those little auto reset breakers can go bad. Check continuity with a ohm meter. or check volts with a vom . one lead to ground and other to either side of "Shortstop" should be volts to ground on both sides. Your convertor may have an internal fuse you don"t see. If nothing at shortstop go into the convertor. Mine has a glass fuse on both the 120 side and 12 volt side.
HiTech
Explorer
Jun 07, 2013
tom496 wrote:
Jim, thanks for replying. Your comment about the inline fuse reminded me of one I'd seen. I just looked again. It's a grey plastic box, maybe 1 1/2" by 1/2" x 1/2" with two poles, it says "SHORTSTOP 12/24V K36 30A", but there is not a button on it to push.

I'll be back with those voltages.

Thanks.

Sounds like that kind of sneaky breaker with a hidden tiny button everyone gets bitten by. If there is no obvious way to reset it (some are self resetting)' check the voltage at each pole relative to ground and from pole to pole (on the off chance that somehow the ground connection opened up).

Jim
tom496
Explorer
Jun 07, 2013
I was only doing visuals on the fuses. I will go out and check continuity on those. Thanks, mena661.
tom496
Explorer
Jun 07, 2013
Jim, thanks for replying. Your comment about the inline fuse reminded me of one I'd seen. I just looked again. It's a grey plastic box, maybe 1 1/2" by 1/2" x 1/2" with two poles, it says "SHORTSTOP 12/24V K36 30A", but there is not a button on it to push.

I'll be back with those voltages.

Thanks.
mena661
Explorer
Jun 07, 2013
Are you checking these fuses with a meter? A good visual inspection does not necessarily mean a good fuse. I've been burnt by that in the past.
HiTech
Explorer
Jun 07, 2013
Sometimes there is a hidden in line tiny breaker on the 12v system with a small button to push. Does not look like a breaker.

It is possible the AC does not come on because the thermostat needs 12v from the furnace, but the 12v system is down.

Just as a starting point what is the voltage at the battery, and at the 12v output of the converter?

Jim

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Urgently Need Help Diagnosing Dead Electrical System

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