Electrical problem... of my own making, I think

[Steve Huber Co-Admin]

David,
As Ed said, the large red cable should have 12V at all times. If you can't access the terminal on the starter but can access the cable, try using a pin to pierce the insulation to see if you can measure 12V between the pin and ground. If you have 12v, then have someone try the ignition key and see if you hear a click from the solenoid. If no sound you are probably not getting 12v from the ignition key.
Steve

[Edward Buker]

David,

The large black wires are grounds that come from the battery and chassis. The large red wire comes directly from the battery bank and is the main current carrier that will get connected to the starter when the solenoid contacts are made. The small wire on the solenoid that comes from the top is the one you are interested in once you confirm that the large red wire has 12V on it. If not the chassis battery switch may be fried or sometimes there is a fusible link large wire in the path to or from the switch.

 That wire coming from the top to the solenoid should have 12V on it with the key in the cranking position. If you do not have 12V at the solenoid wire you can check at the key switch and then if you have it there you know it is lost somewhere in between.

Later Ed

[David T. Richelderfer]

Well...  I have verified the large red cable going from the chassis batteries to the starter solenoid is always HOT.  It should be because it is attached directly to the batteries.  I have also verified the smaller wire going from the front of the coach (the key switch?) to the starter solenoid is COLD in any key switch position... and notably when the key switch is in the START position.  Sooooo... as pointed out we have isolated the problem to between the key switch and starter solenoid.  But additionally, since the generator will not start, we have the same problem between the generator start switch and the generator's starter solenoid - yes?  Therefore, can we narrow the scope of the problem to a common length of circuitry that both the C-12 and generator use in there ignition startup?

Of note the five wires at the back of the key switch are quite small.  Yet the smaller wire going to the starter solenoid is several sizes larger than each of the five wires at the key switch.  Somewhere in the maze of wires between the key switch and starter solenoid the wire size is increased.  My guess is the wire at the generator switch is also much smaller than the wire leading to the generator's starter solenoid - just a guess.  This leads me to believe there may be another pair of solenoids(or something?) that are operated by the key switch and generator start switch in their ignition startup positions... at least there is a place where these smaller wires transition to the larger wires.

How can we have the identical startup issues for both engines?  It seems highly probable there is a common circuit after the rightmost copper buss but before the two start switches used by both the generator and C-12 engines.

[Edward Buker]

Dave,

Your reasoning is sound but it is hard to know for sure if there is a common cause without finding the root cause. One quick check that you can do is along the left copper buss in the electrical bay, there is a row of thermal breakers with one end bolted to the buss. The other side of each of those thermal breakers has a wire attached going somewhere. I think the top one on that left buss is ignition at least on an older Marquis schematic. See if you have 12V on the side connected with the wire at each of those thermal breakers. They should show 12V all the time.

I do not think that there is a relay between the start switch and the wire that feeds the starter solenoid. Just some connections and possibly some plug pins. What is next is to see that one of the wires that comes out of the key switch goes to 12V in the crank position and then backs off to 0 volts when you release it. That wire will have a label on it. That same labeled wire should be able to be found in the electrical bay. If you have a schematic for the coach that covers the ignition switch circuit that would help see if a relay or fuse is involved between the key switch and the starter solenoid. If you have 12V at the dash key in the start position wire, then when you find the same wire labeled in the bay you need to gain access to the conductor and see if it has 12V also when the crank position on the switch is applied. Good to check that wire near where it exits the bay heading to the rear of the coach.

This is a real puzzle because I do not se how a reverse polarity at the battery could have cause current flow that would be damaging to the start switch crank wiring, That should have been an isolated wire with the key off.
Later Ed

[Steve Huber Co-Admin]

David,

I can't find the link to the ignition key in the schematics. However, the start signal to the starter solenoid is circuit 232 (labeled on wire). It's a 14 AWG wire at the starter.
Couple of checks though;  Have you tried starting the engine from the service center (rear passenger side bay)? Also, depending on the options on your coach, there are 2 circuit breakers in the front electrical bay, one on the battery side and one on the ignition side. The one on the battery side should be labeled Ignition Key and the Ignition side one should be Ignition Power. See if both have 12v with key on. If one doesn't it should engage and have 12v when the key goes to start.

Steve

[David T. Richelderfer]

When I put in the new batteries I was in a hurry.  We were scheduled to depart on Wednesday morning for a nice 4-day 4th of July with a brother and sister.  When the engine didn't start initially with the old batteries, I went to Schwabs to get two new ones.  By the time I got the new batteries installed I was running two hours late.  I didn't know I had the batteries in backwards until I switched on the main chassis power and jumped in the seat.  I turned the key, all dead, and turned the key farther, all dead.  Well, by now I have sent the reverse polarity into every nook and cranny possible.  So just about anything connected to those backwards batteries was hit and may be sick.  It's now Saturday morning and I have not departed yet... nay, I have not got the starter to engage yet.  I for years have been licensed to drive, licensed to dive, and licensed to fly.  This is what happens when we get in a hurry and take short cuts without double-checking.  I always double-check the coach before I move it - dish stowed, leveling legs up, basement doors tight, shower door tied closed, pocket doors latched, all cabinet doors latched, slides in, topper awnings rolled in properly with the slides,... even toilet lid down and loo door closed... and lastly, before I put it in gear, check for the travel light.  This is just stupidity at its finest!

I don't have a service center on my coach.  Inside my rear passenger side bay there are both sets of batteries in separate slide-out trays, the two main power shut-offs, a door to the Big Boy and BIRD systems, the high amp ANL fuses, the fuse module, a couple oil filters, two solenoids,....  There is nothing like you have regarding the ability to start the engine and level the coach.  My brother has the 2000 Tourmaline and I am somewhat familiar with his service center.  I don't have such an animal.

But, you guys keep pointing me to check things... and until after the weekend all I have to do is check those things.  At least my checking those things is cheap, eh?  So far I have replaced one ANL 200 amp blade fuse ($10) and have bought a 2-pack of 1n5404 rectifier/diodes ($1.99).  So far that's far cheaper than the fuel and 4-days RV park charges.  So... I'm ahead - right?

[Edward Buker]

David,

I guess you are ahead so far and hopefully it will stay that way and end up a cheap fix. More than 200 amps went some where and if the current paths divided across enough paths to ground it may not be too bad. You might call BCS or Monaco and specifically ask what is in between the starter switch lead and the solenoid on the starter and see if it is more than just a wire. Someone must have a schematic.

I had a bit of a being in a hurry, running late calamity myself this spring. I have a Mini and an Accord set up for towing. I did not know that the Blue Ox removable Pins that lock in the front of the baseplate were different lengths for the two baseplates...never had them side by side. When I ended up with the Mini pins in the Accord baseplate they acted like they locked normally but when I pulled forward lets just say my car was set free except for the safety cables. Very lucky on that one...just a minor Honda bruise....It is an adventure at times.

Later Ed

[Steve Huber Co-Admin]

David,
Again, if you haven't already done so you might want to check 2 circuit breakers in the front electrical bay, one on the battery side and one on the ignition side. The one on the battery side should be labeled Ignition Key and the Ignition side one should be Ignition Power. See if both have 12v with key on. If one doesn't it should engage and have 12v when the key goes to start.
Steve

[Joel Ashley]

Am I safe in assuming that because the tranny is electronic, the neutral safety switch isn't playing in here?

Joel

[Edward Buker]

Joel has a good question here, when you turn the ignition on without going to the start position, does the Alladin come up with a normal screen and parameter readings for a shut down engine and does the transmission panel light up and settle in neutral?

Later Ed

[David T. Richelderfer]

I am not seeing any circuit breakers in the front electrical bay (basement door under the pilot's seat), nor in the battery compartment at the rear of the coach - passenger side.

In the front electrical bay, there is a host of 1" cube relays on the left side of the bay's curb-side wall - 26 of them - with identification "HELLA, 12v, 40a, 4RD, 960-388-46."  These are 5-pin relays as noted in my Google search.  Each relay has a 6-digit number branded/melted onto the plastic cube. There appear to be different brands within the group of 26 relays.  I see at least 3 different brands in the dozen relays which are easily visible.  Some relays have wires attached to all 5 pins, some do not.  The schematic glued to the inner side of the bay door identify each circuit of the group of 25 relays; 1 relay is placed 5 inches away from the other group of 25 - it does not appear on the schematic.

Also, there are 12 different style (what appears to be) relays on the left side of the bay's street-side wall (exactly opposite the 26 relays above).  I am unable to see a part identification number on the group of 12 relays.  Interestingly, the group of 26 relays are all independently attached to that interior wall, but the group of 12 relays seem to interlock together into a long vertical string of cubes.  These appear to be 5-pin as well.  I have no idea what this group of 12 relays is for.  This group of 12 relays does not appear on door's schematic.

The following list is those functions/items that do not work or light up when the key is in any position - ASSESSORY, OFF, ON, and START.
     Kenwood AM/FM/CD.
     Transmission shift keypad left of the pilot's seat.
     Air leveling keypad.
     Cobra CB radio.

In the key Start position the C-12's starter will not engage.

The generator's starter is independent of the key position.  The generator should be able to be started in any key position.  The generator's starter does not engage at any place where the generator is normally able to be started - that being at the start switch on the generator, at the generator's dashboard start switch, at the generator's bedroom start switch, and by the inverter's auto-gen start function.

Almost all other functions normally operated with the key in the ON position are working:
     Blinkers, wipers, headlights, driving lights, mirror adjustment.
     Dashboard lights, and lights associated with the engine, including Little Jake and Big Jake, etc.
     Smart Wheel.
     All gages.
     Hydraulic leveling key/toggle pad.
     SilverLeaf.
     Entry step retract.
    

When the key is in the ASSESSORY position, all things work the same as in the key OFF position, except the Aladdin works normally in all key positions.  I can see the Aladdin screens on the bedroom TV and all readings appear as I would expect with the engine not running.

All these things work independently of the key switch and work normally:
     overhead coach lights, toilet, isle lights, clock on the convection/microwave, TVs, etc.

I hope I have all this accurate.  Whew!

[David T. Richelderfer]

Everything I see in these symptoms points to a common link between the generator and engine start functions.  If it was at the key switch, a burned key switch in the START position for example, then that would not affect the generator start cycle.  It just seems to me that there is a breaker thrown or relay/fuse blown in a circuit used by both the generator and engine start cycles.

[Steve Huber Co-Admin]

Dave,
I'll email you a copy of what I am referring to.
Steve

[Edward Buker]

Dave,

I would take each one of those items that do not work and identify which wire is the power feed. On many of those it may be color coded red but not always. See if you have 12V on that wire. That would begin to inventory which items may be damaged and which do not have power. When you find one without power then see if you can work that wire back to its power source which may include a defective relay, breaker, or fuse. Alternatively you could take a wire and put a crimp lug on the end and a fuse holder with a 5 amp fuse in it. Connect the lug and wire with the fuse protection to the powered buss in the electrical bay and feed the wire end up through the window. For those items that do not have power you could test them with this power source to see if they are operational with power.

In the end there is probably no avoiding physically tracing what the power source is by following wires or a schematic.

Later Ed

[David T. Richelderfer]

I am very pleased to communicate to y'all that yesterday afternoon (Tuesday, July 9, 2013) with the help of a couple friends, and most especially after a quick phone chat with Ken at BCS, things started coming together.

The problem all along has been a lack of knowledge of where to find all the fuses, breakers, etc., to check on.  Let me tell you this - they are everywhere!  For example, we found fuses mid-coach in the basement above the pass-thru storage bay tucked away in junction boxes... boxes that are not able to be seen UNLESS you crawl into the bay and look up between the two major chassis support beams.  But, those fuses were okay.

After chatting with Ken at BCS for five minutes, we learned there are two fuses just under a small removable four inch square plate on the generator.  One of those fuses, a mini auto-style 15a (blue) fuse was blown.  Now the generator starts.

Ken said the problem with the C-12 not starting is the transmission MUST report to the engine that it's in neutral.  Remember, the transmission shift keypad would not light up.  Under the keypad there is a black box, accessed by removing the vertical door that holds the map pocket. In that black box you will find fuses.  One was blown.  Now the keypad lights up and GUESS WHAT, the C-12 starts right up.

So... I still have a few issues.  1) The generator will not start from the inverter remote station above the passenger seat.  But the generator will start from the three start buttons - one on the generator itself, one on the dashboard in front of the pilot's seat, and one at the side of the bed.  2) The air leveling keypad does not light up.  Thus I am unable to level the coach using air.  Notably, the travel light works on that keypad, but nothing else works on the keypad.  3) The Kenwood AM/FM/CD and screen, and the Cobra CB radio still are not getting power.  My guess is somewhere there's more fuses needing to be found.

Hopefully, this morning I will find another black box containing fuses.  I see another, smaller vertical access door just rear of the map pocket door under the transmission shift keypad.  Beside that door is the CD magazine for the Kenwood, and above that door are both leveling keypads.  I think I'll start there first.

While it's not whole yet, I feel like I'm on "final approach."  And I'm quite confident that it's not San Francisco International I'm approaching. The key piece of information came from Ken at BCS.  You just have to have knowledge of where all the fuses and breakers are located.  Otherwise, without that knowledge, especially on a 45 foot coach, you could spend months searching.  I have spent almost a week, off and on, looking per advice from many of you, and I felt I was running out of places to look.

Thank y'all for chiming in.  I was bracing myself for a bill to have the coach towed, plus paying for a technician to fix the problems.  I dodged a bullet here!!  So far, the cost has been a $10 blade fuse, a $1 rectifier diode, and two auto-style fuses.  Oh... and I gave the guy yesterday $50 for his couple hours help.  He works for the local railroad and is a highly skilled electro-mechanical maintenance technician.  He didn't want the $50.  I had to shove it in his pocket.  I do appreciate help... from wherever it comes.  Just call me an equal opportunity "helpee."