No ignition Power

[TomAndPeg]

2002 Dynasty

Hi All,

Last Sunday I switched the chassis and house battery disconnects ON, but upon entering the coach, I had no power to the driver's console or accessories (house power was okay). So I went back and RESET both disconnects; I then had normal power to the chassis and the house. Started/drove/etc. without further incident.

Today when I switched the chassis and house battery disconnects ON, I had power to the the driver's console and accessories, but when I turned around, the power went away. I tried the OFF/ON trick a couple times, but to no avail. I now have no power to the driver's console or accessories, but the house remains okay.

BTW: chassis batteries appear fine. Poking around both the front electrical panel and rear low current panel showed 12.9+ vdc was present on a number of busses with the chassis switched ON.

I'm guessing this is not a fuse because it began as an intermittent problem. Could it be the 80 amp solenoid in the front battery bay below the driver's window? (I'm sure it's original). Or are there other circuit breakers I should be looking at?

Looking for suggestions.

Thanks in advance,

Tom

[RamiDav]

Monaco used some cheap battery switches so you probably have a bad
switch .
Take the sw off and bolt the wires together , if that fixes it go to a West Marine and
buy 2 new ones .
Tape those bolted wires good until you get a new sw .

Ray

[TomAndPeg]

Never thought of the power switch itself, but that's a great idea. I'll try it!

Thanks, Ray.

[YC1]

If you have a bench grinder, sharpen the positive lead of the meter so it can penetrate wires. Keep your fingers out of the way of course.

Carefully push the sharp probe into the insulation of the positive wire but away from the switch in question. You do not want to move the wire or connection.

Your intermittent needs careful measurements and not a hammer approach or you wil not sort it out and be confident it is solved.

Take pictures of where you are going to take measurements. Print those pictures and write your measurements down. Keep those papers in some paper protectors for future reference.

You should be able to sort this in about three measurements..

Start up front in the front run bay and work back to the battery compartment. A couple of measurements in the front run bay and then back to the battery are.

You already checked the batteries so should be good there but be careful to not move the connections on the battery themselves. You need to diagnose the area of problem and then fix it properly.

[Outbound]

Not sure if you have replaced any of your continuous duty solenoids but It sounds like it is time, you have approx. (4) on your rig, (2) in the rear engine compartment which are probably what's causing your problems and (2) in electrical bay below drivers window, next time you have problem turn on ignition switch and tap on solenoids, I'm sure you will find which one is sticking.
Good idea to carry a spare, seems one of them is always acting up.

[TomAndPeg]

Thanks, Outbound. The solenoids are also on my checklist.

[TomAndPeg]

An update:

Started troubleshooting yesterday. Both cutoff switches checked out okay (damn). Metered all five solenoids expecting 15+ ohms and found one good, three at 7 ohms, and one at 2 ohms (I have replacements).

As I was metering power in the rear panels, the chassis power suddenly came back on of its own accord. I thought that was weird: where was the power going? Best guess is a forward bay solenoid but I couldn't find it. Also, the right rear tail light came on unswitched (even weirder).

Instead of fooling with it anymore, I pulled the tail light bulbs, jumped in the coach and drove it to my service center. Whatever the problem is, it's above my pay grade.

Thanks to all for comments/suggestions. I'll relay the final prognosis/solution when I know it.

[TomAndPeg]

Got the coach to Scott's Truck and RV in Rockford, IL where the service team diagnosed a bad battery isolator in the rear high power panel, labelled #3 in the picture below:



I will also be replacing all remaining 12V 80A solenoids.

Ready for the Gulf Coast! Thanks again for troubleshooting suggestions.

[YC1]

Good idea replacing the solenoids.

Your symptoms absolutely do not add up to that isolator. Sorry they just do not.

That isolator is simply a Y connection (electrically though) with check valves. Like feeding two garden hoses from one source. The isolator has electronic check valves to keep the batteries Isolated hence the term.

They probably did not duplicate the problem but may have found the isolator bad. It is not uncommon to have more than one problem.

Hi highly recommend printing out that picture and then take voltage readings on all the posts.

When the problem returns it will be easy to find which component is bad.

Since you are replacing the solenoids the problem will likely be solved. Those things are notorious for failing or having strange symptoms.

[Kurt Averill]

^ This - and don't forget about the grounds - I've seen trouble with a solenoid due to a poor ground, and seen some strange issues from loose screws and /or corrosion in the ground bus bars.

[Gary LS]

I own a 2009 Dynasty and have had a similar problem and found that after changing out the house batteries I did not have any ignition power. After looking around a bit I found a short pigtail with a 10amp fuse at the end of it located toward the rear of the house battery compartment. For some unknown / unexplained reason this fuse was blown.....as soon as I replaced it all was AOK.

On another occasion when the engine would not start I found that there were "*.*" displayed in my transmission screen. After a lot of checking I found that this meant that there wasn't any communication(s) between the engine and transmission. To fix the situation I had to have an Allison tech come to the coach and take out & replace the TCM (Transmission Control Module) at the nominal cost of about $3000.00 and all has been working fine since.

Hope you have the first problem and can get things fixed as easily as replacing this little fuse......and that you do not have a problem like the second....g

[TomAndPeg]

Here are a couple pix of the 120A failed battery isolator.



As you can see in the closeup, the chassis pole arced and broke off, breaking contact:



The replacement is 160A and working great.

[YC1]

I see what has happened most likley and concur it is indeed the isolator.

However it appears the connection probably loostened over time and the resistance built up which combined with heavy current built up heat and there you have it.

In an emergency you can pile all of the wires from the isolator together. A nut and bolt will suffice with ample tape to protect of course.

Do yourself a huge favor and print the picture you posted earlier and then take voltage measurements for future reference. Put the picture in a sheet protector and keep in in that compartment if possible. You will really appreciate it in the future because you won't remember them unless you have a photographic memory.

Thanks for posting the picture of the bad isolator. It would be fun to put an ohmeter on it to see if the internal diodes are still ok.

[Outbound]

Haven't seen that before, very rare, I agree wire must have loosened on connection.