Battery Disconnect Blowing It's Own Fuse

[pholland]

While checking the water level in my batteries in the stepwell I set off the propane detector for the first time after three years of ownership. I didn't know it was that LOUD. I turned off the coach battery disconnect switch also in the stepwell to stop the alarm. After I put the caps back on the batteries and cleared the air of the hydrogen, I turned the battery switch back on and nothing. No power to the 12v system. I located the disconnect solenoid and started checking voltage with a meter. Power to the solenoid but not through. No surprise there but I found two 5 amp blade fuses on top of the solenoid and they seem to be part of it.. One on either side of the power. The fuse on the hot side was blown. I replaced it and tried to turn on the power at the switch and heard a click. The fuse blew. I tried again. Blown fuse. This fuse is hot from the main cable coming to the solenoid and the out side is a yellow wire about 16 or 14 gauge going back into the bundle of wires. The information I can find about this electrical system shows a diagram of the solenoid with the fuse holders on Winnabago's website but no mention as to what this circuit controls.

I part time with my motorhome and it has been parked for several months. I don't normally turn off the battery disconnect when stored as I have solar panels and they keep every thing charged. It has been turned on for about two years. I pulled the battery disconnect switch out from the wall thinking I might be able to test the switch. It has 8 wires connected to it. 4 yellow and 4 white.

Thanks guys. I can rewire a house or a motorcycle but they use different colors. So I what I am asking here is has anyone had this problem before? I can be a parts swapper but I don't understand this system and could swap out much money without understanding the fix. If I was camped way out on BLM land I might be tempted to jump around the solenoid but the fuse is blowing for a reason, but one I can't get.

The motorhome is a 2010 Winnebago Access 24V built on a 2009 Ford E450.

Pat Holland.

Redwood City, CA

[dickandlois]

Pat, Could you post the make and model of your charger / inverter and if there is a part number on the Box you mentioned also. there is very little information on the wiring for your model that I have been able to find.

Rich.

[pholland]

Here is a link to the detail on Winnabago's website. http://www.winnebagoind.com/diagram/2010/10_wire_173846.pdf . The first page gives an error message. Cancel that and scroll down to the bottom page. The solenoid on the left is to connect the coach batteries to the chassis battery for starting. The solenoid on the right is Is the coach battery disconnect. It dosen't have a brand name on it. It has 01-00055-000 21009 B. D. Relay on it. It has the two large cables on the side lugs and two small terminals in the front with wires going into the harness.These two small terminals are not hot at this time. It also has two fuse holders on either side at the top that are marked 7 & 15 and these numbers are inside triangles. 7 is the always hot side of the solenoid and the 5 amp fuse that is blowing. Both of these wires also go into the harness. All the small wires are the same yellow color.

The batteries were outgassing as the solar charger was at max voltage just finishing the charge cycle. I had only removed the caps from these two batteries when the propane alarm went off. I have done this 15 or 20 times since buying the MH new. The other four batteries are AGM as they are in the MH and under one of the seats for the booth dinette The battery voltage is not any different from what I have measured in the past at the different steps in the charging cycle. Solar charger is a Blue Sky with 270 watts of panels. I disconnected the propane alarm and changed the fuse. It blew again when I turned the disconnect switch on.

The charger/inverter is a Parallax Power Supply series 7300, model 7345.

What the wiring drawing dosen't show you is that these solenoids are at the back of a small storage compartment. Arms length away, so it makes it tough to even see whats there. My guesses are that it is 1) a fused relay that is on top of and part of the solenoid and replacement of the solenoid is required or 2) it is a bad control switch and I need to replace it. This a switch that has eight wires connected to it.???. Four white and four yellow.??? Everything was fine until I turned the switch off. Frustrating.

Thanks for your time.

Pat.

[dickandlois]

Thanks for the information Pat. I will look it over and see what I can learn or find.

Makes one wish all of the coaches where wired the same, but then I would get bored !! Keeps the gray matter tuned up.

I will use your information and see if I can expand on it to see how things are connected.

To clear things up for me, does the fuse blow as soon as you install it ? You did mention that its on the always hot side of the solenoid.

Two things come to mind at the time. 1- There is a short in the Solenoid and 2- it could be caused by a shorted diode that was damaged when you opened the circuit disconnect.

Do you have a volt ohm meter of some kind? If so with the disconnect switch open, disconnect the wire from the side of the solenoid opposite the side that has the blown fuse. Measure the resistance between the small terminals, switching the positive and negative probes to see if you read a difference. Red probe on the left / Red probe on the right.

Then if the Solenoid has a metal case measure the resistance from each small post to the case and reverse the probes on each terminal and the case. is there a different reading?

Make a note of each reading and relay that information to me.

Note ! Well I got into allot of information for sure ! around 100 pages,not all related to the coach and chassis isolation and disconnect relays. Now to try to make sense of it all.

Is Your Chassis electrical box right behind the cab passenger door or left of the battery tray farther back of the cab passenger door?

Rich.

[hermanmullins]

Rich,

FYI. I have a 2002 Monaco Dynasty with the Cummins 400 ISL. On the drivers side in front of the Front wheel I have my 12 volt panel. I have two solenoids there along with all of my relays, fuses and my Smart Wheel Control Box. In the Rear in the engine compartment I have two black boxes. Each has electric connections. The box on the right has three solenoids, two 12 volt continuous solenoids and one large (gold colored) solenoid. I believe it is part of the ATS.

Just some more information to clutter up your gray matter.

Herman

[dickandlois]

Hi Herman ! A belated Seasons Greetings to you. Things have just settled down. The kids got home, It snowed 18in. and the grand kids wanted to go ride there sleds. One pooped Pop. And, as I was doing some work on trying to understand how the coach is wired my computer keyboard quit. LOL !!!! So we are running on Blue tooth for a time.

Just adds some sea salt into the mix. I do have the diagrams for the 03 version and if you have a source for the 02 diagrams, I will add it to the mix.

As you read these threads regarding the systems and equipment that are now very commonly used to enhance the coaches, You just know that the chances of a sales person knowing what they all do and how they work is really slim and none !!

When we got our coach and they had the systems person go over things, it was very spotty. I did ask two questions about an item and the blank look was enough to tell me Just Read The Manuals.

Rich.

[pholland]

Rich,

The fuse blows when I turn the disconnect switch to the on position. I hear a click, once, and then the fuse is blown. I had one overhead LED light turned on to see if it flashed, but nothing. The switch is not like a light switch that has definite on and off positions. It rocks to the on position and then returns to a middle position like you are pushing against a spring. Same way with the off position. It has a small light in the rocker part that lights when the 12V power is on.

Testing with a vom is difficult as they mounted the solenoids at the back of a small storage bin. It is arms reach with one arm for me. To get to them I might have to disasemble the whole bin. This is something I think I will take to a Tech as they might be able to replace whats there with something that dosen't have the unnecessary complexity this setup has. A short in the solenoid seems to be the answer.

Thanks, Pat.

[dickandlois]

Hi Pat,

Found out that most of the wires connected to the disconnect relay go to the momentary switch that you mentioned in you last post. The only one that I have not pined down is the designated circuit LK. That one goes to the chassis harness, but it does not show up in any of the circuit drawings I have found to date. The circuit is on one side of the fuse that blows, so you may be correct in thinking its a relay issue.

The bigger issue for me is why did it fail, when you opened the battery disconnect.

The only good idea I have, but no proof to date, is there was a counter EMF spike in the circuit and when you opened the circuit that shorted out the diode inside the relay / across the coil to dissipate that spike and to protect the relay winding.

The spike could have been bigger then anticipated for whatever reason. The measurements I asked you to make might have answered that question. From the drawings I'm working from I can believe you when you mention its a tight spot to work. I refer to them as 10 lbs of parts in a 1 lb. can.

Let me know how things turn out and what failed.

Rich.

[pholland]

Rich,

From your information and someone on the Escapees forum, I called Winnebago tech support to see what they could add. The tech agreed that it does sound like the solenoid has developed a short and that the fuse that is blowing is connected to the switch that controls the solenoid. I took a copy of the wiring diagram and a picture of the solenoid to a local RV repair shop. He also agrees that it is the solenoid and will order one. I will have them install it and keep the old one. I will test it as per your post and post the results here.

Thanks again for the help. I didn't want to walk into a repair shop and say I have no power and hand over my credit card.

Pat.

[hermanmullins]

Pat, here is a quick check of the solenoid. Disconnect the left side cable, cover the end so it doesn't come in contact with any thing, replace the fuse and turn on the switch. If the fuse does not blow then your solenoid has a dead short in it. You can buy the solenoid at O'Reilys, Auto Zone and most any parts house. What you need is a 12 volt continuous duty solenoid.

Good luck,

Herman

[desertdeals69]

If the switch is Intellitec it is a unique solenoid that you don't find at an auto parts store. The "solenoid" is really a latching switch. To go from on to off the polarity is reversed. It only get current during the switching sequence.

[jubilee32]

I have had an issue with the 12v switch on my home. I turned it off one evening as I had no shore power and nobody was on board. Came back the next day, flipped the switch and nothing happened. Off, then back on. Called service tech who thought it might be bad solenoid (was past my pay grade). As we were talking, the 12v came back on by itself. Lit up and has worked since. As we are on a trip, I will not tempt fate again.

Panic is good to get the heart moving in the morning. Thanks for the comments above, I have learned a lot.

[wolfe10]

jubilee32,

Welcome to the FMCA Forum.

Solenoids CAN stick and then free up. Arcing causes pits on the surface of the contacts. These pits can cause the contacts to not make good contact. If this happens again, (assuming you do not want to troubleshoot this with a voltmeter-- which is better), give the solenoid a sharp (but not hard) wrap with the handle of a screwdriver. Many times, that will free up the contacts.