Help with "Start Switch"

[Gordie Allen]

I have a 4104 with a DD671.  I'm starting the rewiring with a new dash, new relay and fuse boards.  The old wiring was a mess with lots of patches dead ends etc.  I assume the ENGINE ON/OFF goes to a relay in the back electrical panel, but what does the relay activate and where is it located?
Thanks,
Gordie

[Cary and Don]

If you are rewiring the whole thing you really need the electrical diagrams and a maintenance manual.  We bought the CD from Coach Info that had all the diagrams on it.  Couldn't have done it without it.  There is a method to their wiring coding.  Each color has a different function.  Hvac one color, lights another, etc. Once you get the hang of it you can guess pretty accurately as to what a lot of the wires are used for.  When you make changes make sure to document everything as you go.  There will be no remembering next week what you did this week.

Don and Cary
1973 05 Eagle
GM 4107
Neoplan AN340

[Gordie Allen]

I found it!  I knew that if I posted this, I'd find the valve.  Kinda like washing your car and then it rains.

[gus]

Pay close attention to the wise words from Don!!

This system is not the simple thing it appears, lots of alarm systems and accompanying selenium diodes (light blue color) complicate matters when you start excluding them.

Once these diodes are wired out of the system all kinds of weird things happen to lights and engine controls.

Unless your wiring is a complete disaster I recommend you wire around the troublesome circuits - you know not what you are asking for!!

This is the voice of hours of frustrating 4104 electrical experience. Leave well enough alone unless you have a very large amount of spare time.