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RMurwin · 01-21-2013, 05:31 AM

I did not disconnect the chassis battery. When I turn the key, or when I try the rear controls, the solenoid engages and a meter shows voltage on the solenoid post that was previously no voltage before the key was turned.

Mike Canter · 01-21-2013, 06:04 AM

That sure indicates that the starter solenoid is bad or a bad connection on the solenoid or starter. That would be a rare fluke that it just happened to fail at the same time that you were working on those 6 v house batteries which have no connection to the chassis system. The only thing that is in common is that you were in the same battery compartment. If it is a bad, dirty or loose connection causing low voltage then why did it start with the screwdriver.

RMurwin · 01-21-2013, 06:14 AM

This is the thing: the wire that leaves the solenoid has 12 volts on it when the key is turned, but the wire attached to the starter never gets that voltage to it. I followed the wire up from the starter and it does not go directly to the solenoid. I don't know where it goes yet, but I suspect that wherever it goes is where I might find the problem. I was wondering if anyone knows where this wire goes so I don't have to tear the wire loom apart to find it.

Mike Canter · 01-21-2013, 06:24 AM

When you say the wire attached to the starter are you talking about the large battery type cable or the smaller wire attached to the solenoid on the starter?

distaff · 01-21-2013, 06:32 AM

RMurwin - you have said a couple of times that there is power coming out of the starter solenoid. For clarity, the starter solenoid is mounted directly on the starter motor. It needs 12v from an ignition solenoid before it closes and passes the heavy current into the starter.

I suspect that you are seeing 12v coming off one of your ignition solenoids. In my coach (and some of my cars) you have 12v out from your ignition to provide power to the computers, fuel pump, and injection, and this comes off a continuous duty solenoid. You also have a short duration 12v output that goes to the starter solenoid on the starter. If you look at the cables going into the starter, they are very heavy and they DON'T originate at the front of the coach.

Is the 12v you say comes off the solenoid you were measuring ONLY present when the key is turned over to "START" or is it always present when the ignition is at "ON"?

You can also test the voltage on your starter solenoid input - I am referring to the small wires not the heavy cables coming from the batteries, but this must be done when the ignition key is at START. We know you have power to the heavy cables because you were able to start the engine.

RMurwin · 01-21-2013, 07:28 AM

Ok, I understand the confusion I have created now. The solenoid that I have been referring to the whole time is the small intermittent solenoid that is not mounted to the starter. I was disregarding the solenoid that is mounted to the starter as being part of the starter, heck, I didn't even know that was a solenoid...
The ignition solenoid is the one I'm able to measure voltage on when the key is turned, the solenoid on the starter does not get powered, but we know that it works because I was able to start it with a screwdriver.
I saw the other (continuous) solenoid, but I don't remember if it ever got powered or not. Should it be on if the key is in the run position?

I apologize for the confusion and thanks to all of you that have responded so far.

distaff · 01-21-2013, 08:56 AM

Thought so. Good to use the same terminology, BTW, just to keep it from being too simple, solenoids are often referred to as relays. This is a picture of the continuous duty solenoid out of my ignition circuit (from the front electrical bay). Mine had a tendency to fail closed so that my engine would not shut down.

This has a fairly heavy cable connected to the main leads, but not the size of the starter cables. It is rated for 75 amps and carries all the current to the computer, fuel injection, etc. If this is what you are measuring, all it can tell you is that with the key in the "ON" position you are getting current to your engine and the engine would remain running when started.

I don't actually know what the circuit to the starter solenoid looks like. Mike Canter who has replied to you already may help with that (he is extremely knowledgeable). What I am suggesting comes down to two points:

* First, if this is where you are measuring voltage, it is not related to the starter and your problem may still be in the front of the coach.
* Second, are you checking the voltage at the small terminals on starter solenoid when someone has the key turned to "START"?

As I mentioned earlier, you can do this alone if you have a multi-meter that records (saves) the high voltage it has seen.

RMurwin · 01-21-2013, 09:08 AM

You sir are very wise and have obviously had experience with people like me before because your picture looks like what I was referring to as the solenoid. I have one just like it mounted in the front of the coach, but that is not the one I was checking. The one I was checking is mounted to the side of the engine bay and it is labeled on the Monaco drawing as "intermittent solenoid". I did check the voltage at the starter solenoid with a meter when the key was turned to "start" and it did not have voltage. I assumed since the one I was checking engaged and disengaged with the turning of the key to the "start" position that it is used in the starter circuit, but I now realize that this may not be the case. I bet that I'm not the first person to say "I wish I had a schematic for this thing".

K7JV · 01-21-2013, 12:03 PM

I have a few schematics for an '94 Dynasty that might be helpful. Some of them are from Monaco, and some of them are of my "creation". Hopefully you might get some good information from them.

Hopefully the attachment will make the trip.

RMurwin · 01-21-2013, 01:21 PM

Yes, the attachment made it.

On page #3, almost right in the middle of the sheet there is a START SOL directly below the STARTER. This wiring configuration is what I expected to find, but mine seems to run to the rear of the coach (have to open the rear motor access door to get to where it goes).

rex · 01-21-2013, 02:12 PM

From the schematic K7JV sent, it looks like the neutral safety switch must close before the Brown wire to the Start Solenoid coil will be energized.

Are you sure the transmission is in neutral?

When you started the engine by shorting at the starter solenoid, did you short the large battery cable to the small terminal (brown wire in the drawings)? If yes, then the start solenoid is not closing. It requires 12v dc to be provided through the neutral safety switch per the drawings.

distaff · 01-21-2013, 07:56 PM

We are getting somewhere (no guarantee it is somewhere good). In the newer coaches some of of what is on the first page is in the front below the driver window. This will send current to the starter solenoid mounded on the starter.

On the first page you have the intermittent solenoid, and the input is wired into the neutral safety AND if you follow the line from the main post it is connected to a fuse on the right that is labelled "Start" and 20 AMP. You need to check your voltages across ALL the possible failure points including the Neutral Safety - to Rex's point, I'd be surprised you could crank it if it was not in neutral since the starter would be turning against the transmission and if your parking brake was set it would stop it, if it wasn't it might move the coach.

Next, on page 3 you have the ignition key on the right, connected to a starter solenoid. It is not clear where this solenoid is located because they also show a thing called the "Rear Star Box" which I guess is page 1. It shows what appears to be a relay or solenoid inside the Rear Start Box, that runs through the Neutral Safety (which I assumes prevents starting in gear), and then to the starter up at the top of the page (if you look closely they show a solenoid is connected to the ignition and two leads that connect to the battery and ground).

You have as possible sources of failure:

The ignition switch itself (low probablity, harder to test)
The starter solenoid that appears to be located near the front of the coach (frankly can't say for sure), better find out where it is
The intermittent solenoid in the "Rear Start Box"
The Neutral Safety
The solenoid on the starter
The wires in between.

The easiest diagnostic approach is to break the system in half logically, and test the front and back and see if you can make a circuit, then focus on cutting the one that fails the test in half. I suggest you make a jumper and jump 12v to the input of the various solenoids and see if you get it to crank to test the back end, and your multi-meter to test the front. Just jump from something that is suitably fused.

RMurwin · 01-21-2013, 09:28 PM

Wow, that is certainly thorough. I appreciate the effort all you guys are putting into this, really. I had to take a trip to Houston for the week, so I'll have to work through these steps this weekend. Some of them I've done already I think, but it would be best to start from the beginning and work through to the end. I'll let you guys know how I make out.

Danjo · 01-21-2013, 09:44 PM

I did the same thing on my boat. Check to see if there is a fuse right where the cable hooks onto the starter. It looks just like a steel block. I found everything else would work but the starter would not work.