generator dead, need help

2800 MicroLite by Onan
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RobertS
Weekend Camper
Posts: 26
Joined: Sun Aug 01, 2010 12:00 am
B190 Year: 1992
WBCCI: 0
Location: Jacksonville, fl

generator dead, need help

Post by RobertS »

1992 B19 with onan gen set.
Last week tuned carb and ran for 20 minutes to clear fuel line with ac running great. As for preventative maintenance I also replaced both the starter relay and auxiliary battery relays next to the radiator.
On the following trip to south Florida the gen set refused to start. Not even a click form the start or stop rocker switch inside or on the gen set. Checked the two 5 amp fuses on the start panel, they were good. Continued on trip.
Later in the day I noticed the van turn signals quit and the push button overdrive located on the shifter failed to work. After replacing the 15 amp fuse, under dash # 5 location about four times, the fuse would fail after five minutes, I located the problem. The auxiliary battery relay is on the same 15 amp fuse.
The brand new auxiliary battery relay failed, shorting out the fuse, leaving the relay open causing the house battery not to receive any charge while driving. Needing turn signals driving through Miami I unplugged the trigger wire connected to the new failed aux relay, replaced the 15 amp fuse #5 location and continued the trip using turn signals, back up lights, and over drive down shift, all on this fuse.

Back home replaced the failed relay, testing new vs the failed unit to confirm my diagnosis, but still no gen set. I have test light tested every fuse under dash, in the Ford van power distribution box, the 50amp aux fuse connector airstream mounts on the fire wall, the two fuses on the gen set, all fuses in the motor home panel under couch, they all test good. The gen set start/stop rocker switch makes no click sound, dead.

I just checked for voltage at the gen start/stop rocker switch in the MH and the two outer leads switch read .05 dc volts. I think they should have 14 volt each.

Need some ideas before pulling the gen set out, not my favorite job.

Robert
1992 B19 E350 460ci
WW White Whale
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skater
Site Admin
Posts: 2569
Joined: Thu Mar 08, 2007 1:00 am
B190 Year: 1991
WBCCI: 13270
Location: Annapolis, MD

Re: generator dead, need help

Post by skater »

I think you're on the right track.

First, did you try starting the generator with the van's engine running? If not, try that, because the 12 volt line for the generator is connected to the coach system (or at least it was in mine), so if there's some problem with the coach electrical system not having enough power, the engine's electrical system should be enough to power it. Check all the fuses in the coach system.

Assuming the coach electrical system is fine, my guess is something happened to the circuit that powers the generator. The 12 volt line to the generator serves two purposes, as far as I could tell: 1. Running the starter, and 2. The generator needed to "see" 12 volts on that line while running, or it would shut down. I never needed to diagnose the wiring for that further, so I don't know how or where it's hooked up, but instead of pulling the generator, I would try to find where that 12 volt wire comes out of the generator box and see if I can trace it down from that point on. This might not be possible, but it's worth trying if it saves you from having to pull the generator.
1991 Airstream B190 - bought, 2005; sold, 2011; bought 2017
1995 Airstream Excella 30' trailer

WBCCI #13270, Washington, DC Unit
User avatar
RobertS
Weekend Camper
Posts: 26
Joined: Sun Aug 01, 2010 12:00 am
B190 Year: 1992
WBCCI: 0
Location: Jacksonville, fl

Re: generator dead, need help

Post by RobertS »

Thank you for the quick thoughts. Still dead with engine running. I will remove the couch seat and test circuits going in and out of gen set. I have down loaded the Onan schematic and trouble shooting info. http://www.cumminsonan.com/www/pdf/manuals/981-0506.pdf You may wish to add it to the site. It suggests if voltage is good to gen set the "start disconnect relay F-1" is defective. This relay F-1 gives 12 volt to starter solenoid circuit until it registers 70 ac volts. I guess it keeps you from engaging the starter while gen set is running. Pages 47 -55 give good info on starting operation of gen set.

I am running a relay race to the finish!!!

Robert
1992 B19 E350 460ci
WW White Whale
User avatar
RobertS
Weekend Camper
Posts: 26
Joined: Sun Aug 01, 2010 12:00 am
B190 Year: 1992
WBCCI: 0
Location: Jacksonville, fl

Re: generator dead, need help

Post by RobertS »

Thank you again for hosting the site with info on how to maintain and enjoy a B19 Airstream.

After checking all three fuse connectors, under the couch seat ( This require removal of seat base,) These fuse/relays are bolted to connector wires, covered with protective tape. They are relays and fuses as used in automobile aps. They all tested good and I re taped them with dated notes.

I decided to inspect the 110 volt relay boxes. I found three crisp overheated, melted wire nuts in the upper gen set relay box. Cleaned the wire connections, replaced the melted wire nuts, I think the 110 volts will flow smoother from gen set. I would suggest owners to inspect the following 110 volt connections:
1 Plug connection wires at end of exterior cord
2 connection box under bath tub for above cord
3 wire nut connectors in gen set relay box under couch

The fix to repair gen set:
One of the two control gen start/stop panel 5 amp fuse holders was broken. both fuses were tested good, but the right holder was not completing the circuit. Jumped the fuse holder, gen set came to life!!! Replaced both holders and gen set works!!!

SS
1992 B19 E350 460ci
WW White Whale
User avatar
skater
Site Admin
Posts: 2569
Joined: Thu Mar 08, 2007 1:00 am
B190 Year: 1991
WBCCI: 13270
Location: Annapolis, MD

Re: generator dead, need help

Post by skater »

Wow, that's a good one. Thanks for the update, and I'm glad you got it working.
1991 Airstream B190 - bought, 2005; sold, 2011; bought 2017
1995 Airstream Excella 30' trailer

WBCCI #13270, Washington, DC Unit
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