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2005 5.7 MAG - No power to dash - Combo switch trips breaker

S

Stelios

Member
Suddenly no electric power at helm / no start on port engine ignition. Stbd engine is fine.
When I tried using the combination battery switch, the engine switch breaker in the cabin would
trip and the starboard engine would also die. Reset the breaker and then the stbd engine will work normally, but
still no elec. power to port engine. Had to come home 15 miles on one engine. Where to start?
 
You have a short
Get a voltmeter and start with the battery, it might be shorted out

There is a short somewhere and start checking and disconnecting until you find that the breaker will stay on
 
AllDodge said:
You have a short
Get a voltmeter and start with the battery, it might be shorted out

There is a short somewhere and start checking and disconnecting until you find that the breaker will stay on
Click to expand...
Battery banks are 12.4 and 12.5

50 amp breaker on engine is good.

Stb engine working normally until i use the battery bank combo switch to try to start the port engine, which pops the stb engine breaker on the cabin panel (keep in mind its the port engine that is the issue). reset breaker and stb engine back to normal

Port engine dash gauges are dead but occasionally will show minimun life briefly. I noticed fireboy indicator light was either very dim or off. But would come on intermittently.

Pushing ignition button port I notice fuel pump does not come on. pushing start button - nothing.
 
I feel your pain but there is nothing anyone on the forum can do to find the short for you. The Port motor has a short which pops the breaker on Starboard when connected together, got it.

Disconnect the alternator wire (orange) from the ALT and see if same happens. With no helm gauges, measure the Red/Purple on the ignition switch to see if you have 12V on it

50 amp breaker on engine is good.
Click to expand...
Good can mean many things, what is your definition or Good when it comes to the breaker?
 
AllDodge said:
I feel your pain but there is nothing anyone on the forum can do to find the short for you. The Port motor has a short which pops the breaker on Starboard when connected together, got it.

Disconnect the alternator wire (orange) from the ALT and see if same happens. With no helm gauges, measure the Red/Purple on the ignition switch to see if you have 12V on it


Good can mean many things, what is your definition or Good when it comes to the breaker?
Click to expand...
no power at port ignition switch terminals (red)
 
Update.
Boat is in its slip with charger on Today I had 13v at the port ignition switch and today i could hear the fuel pump turn on. . I have 12.5v thru the 50amp breaker and 12.5V at the alternator orange wire. This tells me the 90amp starter fuse is ok (i think)
But still cannot get port starter to engage or turn over.
The port batteries are 5 yrs old load tested earlier this summer and were good. And I am showing 12.5v resting
Question. Could it still be a weak or dying battery condition? Even though there are 2 batteries in parallel and also the combo switch was used?
Today the starboard ignintion breaker would not trip when i tried starting port engine with combo switch. So thats something.
 
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