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Fredward · 05-07-2018, 10:57 AM

My neighbor has a new to him 2006 CC Intrigue 530 with C13. After being stored indoors plugged in all winter, all batteries were completely discharged. There appear to be two relays; one in the house battery compartment with the Xantrex and one in the engine compartment with the chassis batteries. We have removed the house batteries and turned off the chassis disconnect switch in the engine compartment. Both of these relays are hot to the touch and they both have 12volts on both sides. The primary lead for the house batteries will throw sparks if you touch it to the frame. The Echo charger is unplugged.

I've looked at the schematics briefly and can't figure out how to trouble shoot. But with the chassis disconnect turned off and the house batteries removed, there should be any 12volt anywhere should there? Are there two boost relays?
Fred

gsander1 · 05-07-2018, 02:36 PM

Fred, if the coach is still plugged in to shore power there will be 12Vdc from the inverter/charger to the house cables. The house disconnect does not interrupt that connection.

Fredward · 05-07-2018, 02:39 PM

Sorry I should add we have the coach unplugged from AC power and the generator is not running.

**CountryFit** · 05-07-2018, 03:16 PM

on my coach, of course much older, there is a power consumption from chassis battery at least from door steps. you would think the steps are powered only by house battery or engine running, wrong. when engne is off, there has to be a power present from chassis battery for it work. there is a relay behind the entrance wall.

phays · 05-07-2018, 04:51 PM

Fredward, As I read my 2000 Magna schematics the chassis disconnect switch only shuts down the front run board circuits. The Allison ECU, starter, and boost solenoid are still connected to the chassis batteries. There may be other connections. I assume the engine computer is still connected.

One side of the switched contacts on the boost solenoid should not have power if the domestic batteries have been removed. If boths sides of the solenoid have power with the domestic batteries removed then the boost coil has been activated or the contacts are welded together. A continuity check between the coil ground connection and a local ground should tell you if the ground wire is shorted between the coil and either of the two switches.

And according to my schematics, if the boost solenoid contacts are closed the house battery disconnect will have power.

Time for the test light and VOM.

Fredward · 05-08-2018, 08:47 AM

OK Phays, that helps. The solenoid in the battery/Xantrex compartment is the house disconnect and the solenoid in the engine compartment is the boost relay. That makes sense. Maybe the boost relay is fried - stuck in the energized position which sends power to the House relay which would explain why we have power all the way up there too.

There are resistor looking devices installed on both solenoids on the low current terminals. Any idea what they would be for? Obviously I need to study the schematics in more detail. It looks like someone has been messing around and jumpering things.

TR4 · 05-08-2018, 08:19 PM

As I remember, the boost solinoid is activated with a ground signal from either the boost switch or the oil pressure sending unit. If the solinoid is hot, try removing the ground wire on the solinoid (there are two small ones). There should be no continuity between the two large connections after the ground is removed. Those small resistors are diodes. When your motor starts and you build oil pressure, your house and chassis batteries are joined so they can be charged by your alternator.

My chassis switch does not disconnect everything, I think the radio and some other items bypass the the switch.

My other solinoid is activated with a signal from the salesman switch at the front door. I bypassed this solinoid because it draws a lot of power and I mostly boondock. I installed a mechanical switch on the house batteries ground.

Bill

Fredward · 05-09-2018, 08:49 AM

Bill,
Good point. I forgot totally about the oil pressure activation aspect of that relay. Another thing to check. Those diodes appear to be burned too. I wonder if they may have failed.

I understand that a diode allows current to flow in one direction only. I wonder what the purpose is in this application. Interestingly in the spare parts that came with the coach, there are extra diodes - the previous owner might have forgotten to mention electrical issues..............

Fred

TR4 · 05-09-2018, 09:52 AM

I’m not an electrical engineer, and don’t have the answer, so I found this;

https://electronics.stackexchange.co...o-a-relay-coil

I’m also interested in this, so I’ll keep reading.

Bill

phays · 05-09-2018, 10:51 AM

Fredward, those diodes are used to allow either the chassis or house batteries to supply power to the boost solenoid coil. The diodes prevent one battery from passing current to the other battery. If both diodes to the coil lead are burnt out then the coil will not be activated by either the boost switch or the oil pressure switch.

Fredward · 05-14-2018, 01:32 PM

Spent quite a few hours on this Saturday. The Previous Owner must have had some problems and tried solving the? Wire #24 from the oil pressure switch was on one lead of the relay and wire 178 from the boost switch was connected to the other lead. And the insulation on the wires from the Oil pressure switch was melted over by the switch so they were shorted. So the relay was energized all the time and shorted to ground all the time. What a mess.
I installed new jumpers and new diodes. Hooked wires 24 and 178 both to one side of the relay and ran new wires over to the oil pressure switch. The I discovered the Oil pressure switch was shorted (or normally closed) when it should have been a normally open 15psi switch so we replaced that as well.

Not sure what caused this sequence of events in the first place. But for sure someone wired the boost relay incorrectly. Maybe the oil pressure switch failed and was replaced with the wrong type of switch (normally closed instead of normally open). But it was an expensive lesson. Wrecked some batteries, melted some insulation could have caused a fire. I'm still not positive we have found all the gremlins but we have the boost relay wired correctly and have restored normal boost relay functionality.

twinboat · 05-14-2018, 02:36 PM

Diodes are there to protect components down the line. Its explained here. Without the diode, you could burn the oil pressure contacts.

Description

A coil spike suppression diode is a protection device across the contactor coil. Energizing the contactor coil creates a magnetic field that forces the solenoid arm to engage the contacts. When the contactor is turned off, the magnetic field collapses causing a back “voltage spike” that can damage the controller. The diode safely suppresses this energy.

https://www.electricmotorsport.com/c...-diode-3a.html

phays · 05-15-2018, 04:11 AM

Twinboat is correct about the use of diodes. You will find that all of the solenoids in the coach has a diode to protect the solenoid coil when power is disconnected. However, with the boost solenoid there are two other diodes that allow either the chassis or house batteries to power the solenoid coil in case one set is bad. Without the diodes, the two sets of batteries would be connected together at the boost solenoid coil.

Fredward · 05-21-2018, 01:41 PM

Now we are having a problem locating a normally open; close at 15psi oil pressure switch. This is what activates the relay to charge house batteries when the engine is running. It needs to have two connections on it. Any ideas?