JJMonaco

Welcome!
Do you have side cameras that work or just the backup camera?  
You need to determine if its the camera or its connection.
If the side cameras work, then you need to check for a failed connection to the backup camera. Hopefully you will find it in the dash area. It could be as simple as it came unplugged.   
On my 2002 Signature, my backup camera did not work when I purchased it.  I tried hooking up a new camera to the original cameras wire. It didn’t work either.  I checked the camera connections in the dash-they were fine.  I then started tracing the wire to the back camera. That’s the difficult part. Eventually I found a break in the wire and spliced it. 
Your other option is to buy a new wireless camera setup.  That’s probably the best solution as the new cameras have much better resolution and are easy to install. 
Good Luck,
JJ
 

To follow up and for future reference-
I removed the Leece Neville DuVac alternator from my 2002 Signature coach.  The mounting ear that was cracked fell away from the  alternator when I removed the lower mounting bolt. So the alternator is toast!  The good news is that I ordered a new 200 amp Delco Remy 28si (Long foot) from Find it Parts on the internet. Only $275.49 tax and shipping included.
In my research to figure out what to do for a replacement, it lead me to the 200 amp Delco Remy 28si.  I wasn't sure if it would be an exact drop-in replacement.  Luckily it was. The belt lines up perfectly.  I used my impact wrench to take the pulley off the old Leece Neville and it fit the Delco. The Delco Remy 28Si alternator is several inches shorter.  Mounting it was much easier than working with the Leece Neville. In hooking up the original accessory/control wiring harness, I used the red wire (constant 12v) for the optional sense wire connection on the Delco 28Si and the grey wire to the R (relay) connection on the Delco 28Si for the tachometer.  I did not connect the yellow wire. (key switch ignition 12v)  The Delco 28Si is self exciting and needs no ignition switch signal to start.  
Something that is important to note, and a prime reason I went with the Delco, was last year I upgraded the house battery system to a 600 amp Lithium Ion (LifeP04) battery bank.  I also added 700 watts of solar panels and a Victron Solar charger. In addition I upgraded original the Trace 3012 inverter to the 3000 watt Victron Multiplus II Inverter/Charger and a Victron Orion DC-DC charger along with other Victron monitoring accessories.  For this reason I no longer needed a DuVac type alternator since the Delco is only charging one chassis battery bank.
Once I got everything hooked up, I have 14.2 volts charging the chassis battery. I have the Victron Orion DC-DC charger's input connected to the chassis batteries. I also have the Victron Orion DC-DC charger on a switch.  That way I can control when I want it to charge the LifeP04 house battery bank when the engine is running.
For reference, I no longer connect and use the original 200 amp battery isolator to separate the chassis and house battery banks.  I also disconnected the Big Boy combiner solenoid. 
Time will tell if the Delco Remy 200 amp long foot will give the 20+ year service life the Leece Neville did. 
Thank you to all that gave me advice and make this so valuable to me.
All The Best,
JJ
 
 
 

I have a 2002 signature as well.  Check your foot switch continuity with a volt/ohm meter when pressed. If it shows any resistance it doesn’t work correctly.  That was the case with mine.  I replaced the foot switch and the jake works as it should.
All the Best
John J