GMC Motorhome Digest V3 #249

[duane m simmons]

Glenn
When you do not get power/voltage between 9 & 1 while cranking the Onan,
this indicates that the control circuit is not functional. Many
components on & off of the control board can cause this symptom. First
thing to test is the 5 amp fuse on the control board & then continue
trouble shooting as indicated in my pass out on the Onan Operation.
Several places can cause this problem & sometimes it is the board. Best
to trouble shoot to eliminate as many as possible before board
test/repair. OBTW I think my Onan Pass out is or will be shown in
www.gmcws.org web site for those that do not have a copy.

Duane

 

[duane m simmons]

Dave & others
The trouble shooting charts in our Maintenance manual is a bit "crystal
balling" it in terms of cause of failure. The conclusion is not possible
as stated in many cases. A simple thing as faulty terminal/wire contacts
can shut you down & is not accounted for in their conclusion. A complete
systematic troubling procedure is necessary before concluding a board
failure & IMPOSSIBLE to conclude (with any degree of certainty) which
component on the board is faulty. The 2 Relays on the board is in the
order of only 20% (or less) of the time the fault (based upon my 4 years
of board repair/restoration). Major fault with the control circuit is
contact deterioration due to exposure to water/weather.
NEVER/NEVER/NEVER hose down the Onan & keep it dry.

Duane Simmons