| Be proactive if you have an Onan [message #306392] |
Fri, 02 September 2016 16:33 |
jhbridges
Messages: 8412
Registered: May 2011
Location: Braselton ga
Karma: -74
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Senior Member |
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In the last week, I've seen two Onan engine control cards toasted because they were overfused. Do yourself a favor if you have a power drawer and you've never looked at the control card since you got the coach. Unless you bought it or the Onan new, pop the cover off the card, remove the fuse, and read the numbers engraved in the side of the end cap. If it says 3AG 5 AMP or AGC 5, fat city. Put it back and worry no more. If the number is anything but 5 (20 seems to be a popular choice) throw it in the glove box for use elsewhere and replace it with an AGC 5. If it says MDL anything, throw it away. There's nothing in a GMC or an Onan which requires an MDL (Slo-Blo is the old term) fuse.
What happens is, the set opens the fuse for whatever reason. There >is< a reason, you ought to find it an repair it. Anyway, there's a box of 20 amp fuses in the coach spares, 20 being real popular in the fuse holder in the glove box. So, someone stuffs a 20 amp in the Onan. Normally, fuses in Onans and most automotive service open from a short someplace, often a frayed or loose wire touching something it shouldn't. When this happens, the fuse, be it 5 amps or 20 amps opens. On the Onan, 5 amps is more than sufficient to run the engine controls, fuel system, and ignition. The components and runs on the circuit card will withstand a short for the time it takes a 5 amp fuse to open and will usually survive. Try to draw 20 amps through the printed runs, relay armatures, and diodes, and they will fail catastrophically (that means the smoke will escape) doing grievous damage to the control card.
Do yourself a favor, check the Onan fuse and replace it with the proper fuse of it isn't a 3AG 5 amp or an AGC 5.
--johnny
Foolish Carriage, 76 26' Eleganza(?) with beaucoup mods and add - ons.
Braselton, Ga.
I forgive them all, save those who hurt the dogs. They must answer to me in hell
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