BAC Forum
General Boards => Technical Support => Topic started by: Mike Jones on August 11, 2020, 01:16:39 PM
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I have 2 power disconnects on my 01 Marquis. One is for chassis and one for coach. When I turn off the chassis disconnect, it shuts off power to the whole coach. The coach disconnect does not shut off anything. I looked at the wiring in the switches and it looks correct according to a schematic that I found for it. And I believe is is only using my starter batteries for house power. If I disconnect my house batteries nothing changes. Any ideas.
Thanks in advance
Mike
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It all most sounds like someone by-passed the House disconnect and routed the cables for the House side to the Chassis disconnect switch. Possibly the one disconnect switch failed and owner didn't want to replace it - however you said the cabling looks correct at both disconnects - could this rerouting have been done at the battery end?
Does the cabling-disconnect wiring setup look like this?
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Mike J,
You may want to check the inverter fuse (250 amp shown in the diagram Mike S provided). It is not unusual for this to fail in the process of changing house batteries and accidentally touch the positive cable to ground. The fuse is hard to see and someone may have relocated the load side cable over to a chassis lug? somewhere. Check and see if your inverter is also connected to the chassis disconnect. If so, this will prove someone has moved the cables. Hope this helps, Fred
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Mike S, that is the same diagram I have and that is how it is wired. It seams that the whole coach is wired to one switch.
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Fred. I do know that the owner before me replace the inverter/charger. Maybe wired wrong?
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MJ, Difficult to get a positive and negative battery cable transposed at the inverter. The diagram the you have and Mike S provided shows a 250 amp "coach" fuse. This is also the "inverter/converter" fuse to protect the unit in the event there is a short or failure. If this fuse is blown, you would have no 12 volt to the coach or the inverter/charger. I would perform an ohm or continuity check across that fuse to verify it is operational.
If you had the ignition key on or the engine running that would tie everything together. What is the voltage in the house batteries? If the house batteries are tied to the chassis batteries the voltage will be equal. Check one last time and see if there is a cable going from the chassis batteries "positive" over to the house battery "positive". Hope this helps, Fred
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Fred, the fuse is good, I checked the voltage on both circuits with engine off and they are different. The main issue I am having is it seems that all the power is running thru the chassis circuit. When I shut the coach circuit off everything still has power. When I shut off the chassis circuit it shuts off everything. I checked to see if the battery power cables were connected to the same terminal and they are not. Seems like both circuits are connected together somewhere. So when I dry camp it is using my start batteries for power and not my house batteries. Guess I will need to see where the circuits connect to coach just not sure where that is.
Thanks
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Mike,
There are 2 cables that you can trace to determine the apparent mis-wire. As mentioned earlier trace the + cable on the inverter to its source. The other cable is the one that comes to the front electrical bay and feeds the coach buss bar, located to the left of the chassis battery buss bar and solenoid. Using a tone tracer will make the task easier if you have one. You could also trace the cable feeding the DC breaker box.
Steve
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Thanks Steve, I will check that also.
Thanks
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Mike J,
on my 2002 Marquis, I had a battery isolator that was mounted just above the batteries in the left rear battery compartment. Did not have a solenoid that tied the batteries together that is in your schematic. Possibly one or both of the diodes failed in the isolator. Possibly miswired at isolator. There are 3 terminals on the isolator, middle one is from the altanator, the outside two go to each set of batteries. If you have a Echo Charger, it will be wired into the isolator as well. This might be a good place to start troubleshooting. Hope this helps,
Frank.
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Frank. I checked the isolator and it seems to be working correctly.
Thanks for your input
Mike
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Mike,
Another common mistake that is made on older coaches is the LP detector. The original came with 2 red 16 gauge wires and the black ground wire. One of the red wires was connected to the chassis batteries, the other red wire was connected to the house batteries. When the detector is replaced, the new one only has 1 red wire. Sometimes the person doing the repair twists the 2 red wires together and connects them to the one red wire. This repair has now tied the chassis and house batteries together. Might be worth a look. Hope this helps, Fred
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Mike J,
the only other place that the battery banks could be tied together other than the battery isolator that I know of, is the battery boost solenoid. I believe it is mounted in the top, center of the battery compartment. Possibly failed in the closed position. Hope this helps.
Frank.
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Fred I will take a look at that.
Frank, I checked the voltage at the boost solenoid and the voltage on one side matched the start batteries and the other post matched the house batteries voltage, so I believe it is ok..
I haven’t had a chance to check the inverter circuit yet. But I do know the previous owner replaced it before I bought it so I am not sure which circuit he connected to.
I checked the power circuits in the Electrical compartment and when I shut off the house disconnect switch everything still had power. So not sure what it is connected to.
I am beginning to think he hooked both leads to the elec compartment together somewhere.
Thanks for everyone help
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Mike,
That being said, look at the ignition solenoid in the front run compartment below the drivers seat. That solenoid is a very common failure and one that eventually you deal with. Not uncommon for it to fail while in transit or on an adventure. The fast fix is to remove one cable on one side of the solenoid and then piggy-back it on top of the other cable to get you going until you can replace it. Another situation is the solenoid fails and gets replaced with a solenoid that is NOT continuous duty rating and they can fail in the "on" position. Most of us carry a spare Cole Hersey solenoid and a spare Delco Remy ignition switch. because of the failure rate. Hope this helps, Fred
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Fred.
Will do
Thanks again
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The continuous duty ignition solenoid in my Monterey and many others is Cole Hersee 24059, but you should check the model numbers on yours. See online if it’s continuous duty, and if not there’s at least part if not all of your problem; someone installed the wrong solenoid. But also don’t assume the Cole Hersee 24059 is correct for your specific Marquis; others here may know, or call BCS in Bend.
http://colehersee.com.au/product/spst-12v-85a-continuous-duty-solenoid/
It’s available at numerous auto parts outlets and Amazon. If you do determine to replace it, take note of the diode between the small posts and make sure you put it the same way on the new device... with its stripe on your left.
Joel
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Hey guys the ignition solenoid is the switching gear for the automotive accessories and is powered by the chassis batteries.
As witch a failure should cause either accessory power all the time or no accessory power at all ( ie lights,heater,etc)
In either case it should not connect the coach batteries to the chassis batteries unless I'm missing something .
How ever the boost solenoid if stuck in the closed position would cause the two battery banks to be connected together.
And if the system has an echo charger or Magnum battery combiner the problem may be found there .
But as Fred pointed out the first place to look would be that propane detector I've heard of a couple of those wired wrong.
Eric
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I checked the propane detector. It is the original and the red wires are connected separately. So I will keep looking.
Thanks
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Mike, I know this is difficult and extremely hard for us out there in forum land. The last thing we want to do is send you down some rabbit trail. Now that we know that you have a handle on troubleshooting we need to figure out how to divide and conquer this enigma. On the frame rail behind the battery tray is an insulated lug. This is the distribution point that the 12 volt house battery sends voltage to various loads. I would disconnect the chassis battery and start tracing how far the house 12 volt power goes before it stops. Hope this helps, Fred
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Fred, I will take a look at it. Trying to finish up my dash ac also. Compressor froze up. Always something, never boring. lol
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Others may have said this already, but I'll take a stab; If the chassis sw shuts off all power, the problem must be ahead of the chassis switch, that is, between the chassis battery and the chassis switch. This may sound too simple, but have you simply taken the house + cable and reattached it to the house switch? Careful with all the sparks!
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Mike,
Have you checked the salesman switch solenoid to see if that is allowing 12 volt to pass thru it when the battery switch at the entry door is turned on? (the solenoid with black oval). Fred
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Mike
I would check the coach battery grounds at both the batteries and the frame connection if the frame connection or cable has gone bad your coach batteries will be unusable.
If this is the problem someone may have bridged the boost solenoid to regain coach power .
I would Disconnect one side of the boost solenoid to see if you lose coach power this with check to see if that solenoid is activated if stuck closed .
If that kills the coach power then check the coach batteries grounds you could check that by simply connecting a booster cable from the batteries ground terminal to a good chassis at or near the grounding point on the frame effectively bipassing the coach battery ground cable.
Hope this helps
Eric
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Fred. I checked the salesman switch and it let’s power go thru but if I shut the salesman switch off all the lights still work.
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Bill and Eric. I will try some cable tracing this weekend. I will look into your suggestions.
Thanks
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Mike, after turning off the salesman switch you need to check the solenoid to see if it is passing through 12 volts. You could have a defective switch or solenoid that is not opening. Make sure the batterys are fully changed with clean terminals and disconnect shore power. With someone operating the switch you can put a voltmeter on the solenoid output to verify it’s operation. Good luck.
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Guys
All his symptoms seem to indicate his 12v coach power is coming from the chassis batteries, thus the salesman switch and solenoid don't have any effect.
Steve
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Everyone,
I spent some time looking at my electrical issue. I disconnected and cleaned and ohm tested my ground cables. Even connected jumper cables on the ground cable circuits. Disconnected all cables at terminal in basement. What I found is, I have a voltage feedback on the cable coming out of the coach to the terminal connection when it is disconnected from that terminal. I checked the solenoid in the electrical area under the drivers seat and I have some feedback on the ignition solenoid. @ 5 volts. So I am thinking I my have a relay stuck somewhere in the ignition circuit. Headed on vacation Friday, so will have to look more when I get back. At least I will have shore power while on vacation.
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I have had two "somewhat similar" situations on my 98 Patriot.
1. My solar chargers were wired directly to the batteries bypassing everything. Easy test is to put a dark color blanket over the panels to block all the light from the solar panel and see what your voltmeter says.
2. Mine has a huge screw together connector down underneath the main 12 volt door (below the driver seat with outside access. I once had some kind of short I finally identified. Rather than unscrew that big connector (it has like 40+ wires), I traced the issue and simply decided to add a wire that connected the intermittent internal connector short wire across the outside connector wire in that big bundle. Been fine now for over 10 years. Now sure what is in and under your coach. (bypassed that wire causing the problem)
Larry Fritz