1997 Monaco Windsor House power shuts off when ignition turned on

[dusher]

I am sophisticated with electricals but need some help from somebody who knows 1997 Monaco Windsor Diesel or similar RV. There are two issues apparently related:

1. The house power turns off (including interior lights, radio etc) when the ignition is turned on.
2. The engine battery is not being charged on shore power but is charged when engine is running
3. It is 38 foot with diesel engine under the rear bed. Various relays and power equipment are mounted on the front wall of the engine compartment.
4. The RV has a 2000w heart inverter and AC power transfer switch that appears to be working fine.

Here is what I see:
1. The fuses panel is behind a pullout at center of dash at floor level. There is a black 8 guage wire going to a house power fuse barrier strip at upper right. All fuses test good. The black wire on this barrier strip appears to go to a battery disconnect relay in the engine compartment (which I replaced to no avail).
2. When I turn the ignition on, a battery disconnect relay at upper right of the fuse backplate connects power to the running equipment fuse block barrier strip. That is working fine.
3. The 8 guage house battery fuse terminal block black wire appears to go to the engine compartment to a battery disconnect relay lug which has another 8 guage black wire going somewhere else (see engine compartment new relay lower right). I do not know where the other black wire goes. Where does it go? That relay is not getting power to the coil under any circumstances. That relay has 12v on the on one contact that comes from a large rectangular device that has fins on it. I think that is a bridge rectifier.
4. The house lights come on if I jumper across the relay. I think this relay is supposed to turn on when the ignition is on. I replaced the relay today but that did not fix the problem (see photo with new relay).
5. POSSIBILITY: whatever controls the coil of the battery disconnect relay (which I replaced) might not be working. There is a purple wire going to the coil. But what pulls it down?
6. When somebody toggles the ignition key switch, there are about 8 smaller control relays mounted high in the engine compartment, some of which click. One is labeled "ignition" but its wires are yellow/white and do not appear to go to the battery relay. I tapped the relays to see if that power up the battery disconnect. That did nothing.
7. There is another old battery disconnect relay at upper left of engine compartment (see photo) but it has small wires and does not appear to go to the new relay I put in. I do not know what it does.
8. I looked for more hidden relays such as under stove in slideout. i do not see any hidden equipment
9. (Related?) problem: Engine Battery Not Charging: I'm not sure where 12v comes from to charge the engine battery. The House batteries are getting 13.73v charge current on shore power and when the engine is running. The House battery There is a big blue CH battery isolator with huge wires at right of front of engine compartment and a green Lambert LE-514 battery maintainer/protector. I have not look into that equipment yet. If you have any tips as to why that might not be charging the battery please advise.

Conclusion so far:
1. Whatever powers the purple wire on the coil of the new battery disconnect relay may the key. I do not know where that wire goes (hiding in loom). That wire does switch to ground ... the other side of the coil always has 12v . The house lights do go on when I jumper the contacts.

[Skip426]

JMHO: Your coach was probably not set up to charge the chassis batteries , when on shore power from the factory . Many owners have had to add equipment to charge the chassis batteries.
I'd be very careful checking out any equipment and wiring that doesn't appear to be from the factory , and the green finned unit on the left side of one of your photos; and it's wiring , appears to be added.

Your year of RV must have been one of the last to use the " dual battery isolater" the blue finned box with the three heavy cables . Within a few years of your RV, being built , most manufacturers had switched to other more durable battery inter connect systems. ( BIRD for example)

I'm going to download your pictures to a larger computer with a HD screen , to see if I can blow them up for more detail than is possible on my lap top.
If I can pick out any issues that could pertain to your problems , I'll re-post.

[twinboat]

As far as charging the chassis battery with the house charger, the green box, in the upper left corner of the 3rd picture, handles that.

On that same picture are manual disconnects and breakers along with the large finned isolator. Below the isolator is the boost solenoid.

The boost solenoid only comes into play when the boost switch is pushed. Its not like the more modern isolation solenoids.

With the disconnects off, you should have chassis battery voltage at one disconect and house battery voltage at the other. The other ends of the cables could be on the wrong batteries or left off completely.

The isolator is a double diode with the center tap connected to the alternator output. Each outside tap goes to each battery for charging. Make sure that is working by running the engine and checking for charging ( 13+ ) voltage on the center and both outside terminals. No increase on the outside ones means the diode failed.

When checking the many circuit breakers, confirm equal voltage, not just voltage, on both sides of it. That confirms they are good.

In picture #4 on the new solenoid, is the small black wire going to ground or to the big post with the larger red cables.

If its going to battery and not ground, that may be your problem. The other small wire may be supplying a ground until you turn the key on. When you turn the key on, that solenoid could be opening, shutting down the house power. The purple wire is not the ground and the black wire should be.

[Skip426]

Originally Posted by dusher

9. (Related?) problem: Engine Battery Not Charging: I'm not sure where 12v comes from to charge the engine battery. The House batteries are getting 13.73v charge current on shore power and when the engine is running. The House battery There is a big blue CH battery isolator with huge wires at right of front of engine compartment and a green Lambert LE-514 battery maintainer/protector. I have not look into that equipment yet. If you have any tips as to why that might not be charging the battery please advise.

Conclusion so far:
1. Whatever powers the purple wire on the coil of the new battery disconnect relay may the key. I do not know where that wire goes (hiding in loom). That wire does switch to ground ... the other side of the coil always has 12v . The house lights do go on when I jumper the contacts.

OK , twinboat covered a lot of what I'd started to figure out.
The Lambert battery maintainer , by the wiring is more than likely an add on and isn't functioning , personally I have no idea how it would be activated .
The purple wire , " does switch to ground " would make that relay , what I've always referred to as " low side driven " if you have ground showing on your multi meter ohm scale, ( zero ohms ) and that relay doesn't activate then the ground is applied , it could be that poor ground is the issue. If you supply a separate ground to the terminal with the purple wire , does the relay activate?
When you say " jumper the contacts " , are you going from one large terminal to the other large terminal ?

EDIT : BTW, the new relay , did you get numbers off the old relay to purchase it or was it a " looks like what I have " purchase?

[twinboat]

I don't believe the relay ( solenoid ) is switched by ground, or low side driven.

I believe he assumed its a ground activated relay, because he has mistakenly connected 12 volt power on the other side.
That short wire should go under the mounting bolt, not the B+ post.

If he was to ground the other small terminal, not powering it, with the small black wire, I think it will work normally. If not it won't hurt any thing trying.

[dusher]

The green finned thing is a Lambert LE415 battery maintainer that came with the bus. It has a 5amp 3 stage trickle charger. when it sees 13.5+ volts being sent to the house batteries, it sends it to the coach battery. It appears to be working.

[dusher]

The new relay is a generic 25A continuous duty relay. 12V+ from battery isolator is on the left relay contact with a jumper to the left coil term. The right relay contact has 2 black 8GA wires, one of which goes up to the fuse barrier buss. I don't know where the other one goes yet.

So, the purple wire goes to something that makes a connect to ground to activate the relay. I electronics this is called "current sinking" or in control panels it is usually called "switch to ground". I am not seeing that wire go to ground under any circumstances. I'm hoping that a Monaco expert knows where it goes to.

I figured out that charge 12v comes from the Heart inverter. It is definetley doing something -- A am seeing 13.3 volts when it is turned on but I am bothered that it is not showing amps on the charge when plugged into shore power.

[guardrail53]

[QUOTE=dusher;4211633]The new relay is a generic 25A continuous duty relay. 12V+ from battery isolator is on the left relay contact with a jumper to the left coil term. The right relay contact has 2 black 8GA wires, one of which goes up to the fuse barrier buss. I don't know where the other one goes yet.

So, the purple wire goes to something that makes a connect to ground to activate the relay. I electronics this is called "current sinking" or in control panels it is usually called "switch to ground". I am not seeing that wire go to ground under any circumstances. I'm hoping that a Monaco expert knows where it goes to.


The salesman relay/switch, controlled by the on/off switch by the front door! The purple wire goes to the switch by the front door!

I bypassed mine, saw no need for it! Rail!

[twinboat]

Originally Posted by dusher

The new relay is a generic 25A continuous duty relay. 12V+ from battery isolator is on the left relay contact with a jumper to the left coil term. The right relay contact has 2 black 8GA wires, one of which goes up to the fuse barrier buss. I don't know where the other one goes yet.

So, the purple wire goes to something that makes a connect to ground to activate the relay. I electronics this is called "current sinking" or in control panels it is usually called "switch to ground". I am not seeing that wire go to ground under any circumstances. I'm hoping that a Monaco expert knows where it goes to.

I figured out that charge 12v comes from the Heart inverter. It is definetley doing something -- A am seeing 13.3 volts when it is turned on but I am bothered that it is not showing amps on the charge when plugged into shore power.

A 25 amp continuous duty relay sounds to low an amperage, but thats beside the point.

Remove the short jumper, from hot to the pull in coil terminal. Now ground that pull in coil terminal and test the relays operation.

[dusher]

guardrail53 gets the cookie for figuring it out. thank you very much!

Now I feel like an idiot. I have been doing control systems for 30 years and thunked my way down the rabbit hole.

The battery cutoff switch was indeed turned off. Gag me with both farm animals. I never used it for anything since I keep it at home and plugged in for a guest cottage.

I had been messing around trying to figure out where to wire in a low-voltage cutout to the steps. I have lost two motors in 18 years of RV'ing due to low voltage when the step goes up. The timer circuit in the kwickee controller does not work in low voltage scenarios and it burns up the motor. I got a really nice little cutout circuit board on ebay for $4 with adjustable cut-in/out that draws only 1ma. I will have to put it in a waterproof box underneath .... no place to put it upstairs.

I really got snockered on the cutoff switch. With the cutoff switch off, the boolean logic of the RV wiring causes some very unexpected things. The House lights should not be on but cut out when I turn on the ignition. I would expect that the cutout would kill all circuits for house and engine. But no, everything still works -- unless I turn on the ignition!!

But this was a grudgingly worthwhile exercise. I now know what all the electrical controls do in the engine compartment and how they interact with the front fuse backplane. I also know a lot more about how the Heart inverter works and what the idiot lights on the Heart remote mean. If I have a problem on the road I will be ready for showtime.

[Skip426]

Glad you've got things operating , thanks for wrapping up your post.

As with most problems with electrical systems , pinpointing the problem , takes 99% of the time.