| Re: On the Road Electrical Trouble-shooting [message #334544 is a reply to message #334536] |
Tue, 03 July 2018 22:43   |
Ken Burton
Messages: 10030
Registered: January 2004
Location: Hebron, Indiana
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You have a lot of extra (different) stuff there from the way the coach was designed. The extra stuff makes remote diagnosis difficult because we do not know exactly what you have there. So my approach will be to explain the two 12 DC electrical systems that you have in the coach as shipped by GM in 1977.
There are two 12 volt DC systems. They are the engine side and the house side. There is NO Boost system with it's own batteries. There is a VERY SELDOM USED boost function that temporarily attaches the house and engine batteries together for extra starting power in the case of one battery (house or engine) being low. This is so seldom used that on my coach I have never, ever needed it. This function is activated by pressing and holding down a rocker switch on dash.
So back to the two systems.
The engine side normally has one battery located above the right front wheel. I supplies all power for starting the engine and things you expect to see in a car. Things like headlights, brake lights, clearance lights, front only interior lights, radio, and heater fan. If it is an outside light or and item located in front of the cockpit step is is probably powered by the engine 12 DC system.
The house side in a 1977 26 ft coach is normally powered by one or two batteries located in the left rear of the coach next to the Onan. Everything not mentioned in the previous paragraph is probably powered by the house battery(s) system.
That is it and things like blue and green arrows and a battery mounted on the driver's side front mean nothing to us because they are non-standard add-ons.
All of that said, I can not see why these non-standard add-ons would be on the engine side of things. People usually install that stuff to extend / expand the house system. There is really no reason that they would be needed on the engine side.
So I would check the engine battery and check it's connections and ignore everything else we think is on the house side. From your symptom I strongly suspect that one of the following items are failing or out of adjustment in the following order. The neutral safety switch, the ignition switch, the start solenoid coil, and wires/ connections to any of them.
They next time that you have the failure, while it is failing turn on the headlights and try starting the engine. If the engine fails to crank and the headlights stay on then you do NOT have a battery power supply problem. If the headlights dim, then you need to go find the bad battery connection or weak battery.
That should get you started diagnosing the problem. Also the next time is fails try moving the gear shift up and down while trying to crank. That will move / exercise the neutral safety switch a bit.
Good Luck
Ken B.
Ken Burton - N9KB
76 Palm Beach
Hebron, Indiana
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