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Generator fan wiring

I should call this the third in a series on trying to solve my problem with generator fan not working.  A major obstacle has been that there seems to be no wiring diagram for the 120v circuit that supplies the fan motor.  The 120v wiring diagram that shows all the wiring and connections in the coach shows nothing around the generator.  The wiring diagram for the generator control box is 12v and does not show the 120v side of things (45A CBs, cooling fan CB, or fan motor).
  Because of this, I've had to "dive in" and map where I observed the wires to go, starting at the fan motor.  I opened junction boxes, moved relays and cut a "thousand" zip ties to follow the wires.  To save a lot of explaining, I included a photo of my diagram (not to be confused with a proper "wiring diagram").  It is not to scale, but shows everything I was able to get to.
This still left me with some questions and I may have to call Jeff at Power Tech in the morning.
Some things I'm not understanding:
1- In a 120v circuit, I expect to see power going from a source, to switches (relays), circuit breaker, an appliance (motor, lights, outlets) and then returning to a neutral power buss of some sort that completes the AC circuit.  I don't see how the 10A CB is in that circuit, from what I've observed.  It is connected to the power source (45A relay) and the ground.
2- The black wire from the fan goes directly to the hour meter (front of panel) and the only other wire from that goes to the run relay, which is 12v.  Does that run relay act to close the 120v circuit?  In addition to the hour meter, the run relay also serves the run solinoid and fuel pump.
3- The white wire to the fan comes from a (+) terminal under the latching relay and that is energized by a wire from a 45A CB.  I have no idea where the other wires (4-5) fo from there.  Transfer switch under the bed?

We have used the generator very little since we bought the coach and it is possible that the fan never worked during that time.  I've considered that someone else, previously, may have misplaced some of the connections.  If any of you have an electrical background, I'm hoping you might have some answers.
Reminder from earlier postings:  The fan motor works fine when connected to another 120v source and I am getting power from the generator to the coach - just not the fan.  Ohm meter shows good continuity in the white and black wires to fan.

2000 U320 mid entry  #5688
2006 Jeep Liberty


USMCR retired
SDFD retired
FEMA US&R TF8

Re: Generator fan wiring

Reply #1 –
Sven, can you unhook the wires at the fan and check to see if the wire coming out of the cb is still showing ground? if so it is shorted. If it went to ground the cb would pop instantly. When the fan is hooked up it would show ground as the fan motor itself would make the wire ohm to ground.
1999 40 ft. U-320 wtfe build 5563 Chuck & Lynda's "Rollin' Inn"  2030 watts solar
prev. mh's 71 GMC 5 yrs. 73 Pace Setter 1 yr. 78 Vogue 5 yrs 81 FTX 40ft all electric 18 yrs. 1996 Monaco Signature 3 yrs.
2014 Grand Cherokee Overland
Dream as if you will live forever. Live as if you will die today.  James Dean

Re: Generator fan wiring

Reply #2 –
Quote from: craneman –
Sven, can you unhook the wires at the fan and check to see if the wire coming out of the cb is still showing ground? if so it is shorted. If it went to ground the cb would pop instantly. When the fan is hooked up it would show ground as the fan motor itself would make the wire ohm to ground.
I did that and it initially showed ground.  I followed the white wire to the junction box behind the generator, disconnected it to see if ground might be between there and fan - no ground.  I then took it off the white post at the (+) terminal under the latch relay and there was no ground between it and the junction box.    I reconnected the wires in the junction box (connecting the two wires) and no ground.  There did not appear to be any damaged wires in the control box, so I could not find a ground there.  Did you see from my diagram where the fan CB relates to the circuit?
2000 U320 mid entry  #5688
2006 Jeep Liberty


USMCR retired
SDFD retired
FEMA US&R TF8

Re: Generator fan wiring

Reply #3 –
I may be oversimplifying things, but if blower is fine on external ac power, and gen is producing power, why not just take power from gen. 45 amp circuit breaker, and put your small  10 amp CB in wiring from 45 amp breaker to blower?  That way blower is powered when gen starts producing power and shut down when gen does.
Jim C.
coachfree, previous 1997, 1999, 2000, and 2003 Foretravels.

Re: Generator fan wiring

Reply #4 –
I would recommend that you get a signal tracer and starting at a known source, trace every wire to its end.  Make a sketch as you go.  When you have a grip on the wiring and components within the system, then you can trace voltages and diagnose the problem.  Sounds like you may have a component problem (relays are always a suspect).  I doubt that you can find a schematic and so making your own is all you can do in that regard.  Good tracing and have a great day  ----  Fritz
Fritz & Kathy Johnson
1991 36'

Re: Generator fan wiring

Reply #5 –
Quote from: jcus –
I may be oversimplifying things, but if blower is fine on external ac power, and gen is producing power, why not just take power from gen. 45 amp circuit breaker, and put your small  10 amp CB in wiring from 45 amp breaker to blower?  That way blower is powered when gen starts producing power and shut down when gen does.
Seems simple enough - Disconnect 10A CB from 45A CB and ground  put it on the hot (white) line between fan and 45A fuse?  Makes sense, but I'm still trying to understand why it is where it is, before rewiring.  There is some reason it is tripping - incorrectly wired to begin with?  Will have to check with Power Tech before messing with it.
2000 U320 mid entry  #5688
2006 Jeep Liberty


USMCR retired
SDFD retired
FEMA US&R TF8

Re: Generator fan wiring

Reply #6 –
Quote from: fkjohns6083 –
I would recommend that you get a signal tracer and starting at a known source, trace every wire to its end.  Make a sketch as you go.  When you have a grip on the wiring and components within the system, then you can trace voltages and diagnose the problem.  Sounds like you may have a component problem (relays are always a suspect).  I doubt that you can find a schematic and so making your own is all you can do in that regard.  Good tracing and have a great day  ----  Fritz
I already did that, visually.  Is there something in the photo that is missing?
2000 U320 mid entry  #5688
2006 Jeep Liberty


USMCR retired
SDFD retired
FEMA US&R TF8

Re: Generator fan wiring

Reply #7 –
If the 10 amp breaker is hooked to ground then it is a direct short and it should then trip. Must be miswired.
previous 1984 35 ft ORED 250 HP 3208 Cat       
previous 1998 40 ft U295 CAI 325 hp Cummins
previous 2003 40 Ft u320 build #6140 450 Cummins M11.                                                         
1999 Mazda Miata
Ron, Nancy, Tipper the cat, Max The dog
1997 U 270 36 ft build number 5174 8.3 Cummins

Re: Generator fan wiring

Reply #8 –
Quote from: red tractor –
If the 10 amp breaker is hooked to ground then it is a direct short and it should then trip. Must be miswired.

I had questioned the 10A CB wiring, and I can see it tripping because of the ground.  However, if it is not in the circuit, it should not prevent the fan from coming on.  Right now it isn't protecting anything - it is just taking a hot lead to ground, tripping (or melting) the CB along the way.
 If I were to take the hot lead (white) wire going to the (+) terminal (under latch relay) off the 45A CB and connect it to the 10A CB, where the ground wire is now, that should put it into the circuit.
2000 U320 mid entry  #5688
2006 Jeep Liberty


USMCR retired
SDFD retired
FEMA US&R TF8

Re: Generator fan wiring

Reply #9 –
The hour meter should be working with 12 volts not 120 volts
previous 1984 35 ft ORED 250 HP 3208 Cat       
previous 1998 40 ft U295 CAI 325 hp Cummins
previous 2003 40 Ft u320 build #6140 450 Cummins M11.                                                         
1999 Mazda Miata
Ron, Nancy, Tipper the cat, Max The dog
1997 U 270 36 ft build number 5174 8.3 Cummins

Re: Generator fan wiring

Reply #10 –
In looking at your drawing again looks like someone hooked the ground for the hour meter to the 10 amp circuit breaker and the black wire to the motor to the hour meter. The black wire should go to the 10 amp circuit breaker p.utting 120 volts to the fan motor and then the ground to the hour meter which appears to get its 12 volts from the relay on the side of the control box
previous 1984 35 ft ORED 250 HP 3208 Cat       
previous 1998 40 ft U295 CAI 325 hp Cummins
previous 2003 40 Ft u320 build #6140 450 Cummins M11.                                                         
1999 Mazda Miata
Ron, Nancy, Tipper the cat, Max The dog
1997 U 270 36 ft build number 5174 8.3 Cummins

Re: Generator fan wiring

Reply #11 –
Your wire from the 10amp breaker that you show going to ground is the power line to the fan motor on my generator.
Regards,
Brett

'99 42' Foretravel Xtreme
'14 Brown Motorsports Stacker
'05 Chevy SSR
'02 BMW R1150R

Re: Generator fan wiring

Reply #12 –
Quote from: amos.harrison –
Your wire from the 10amp breaker that you show going to ground is the power line to the fan motor on my generator.
This is the conclusion we are coming to.  Is it the black or white wire going to the 10A?
2000 U320 mid entry  #5688
2006 Jeep Liberty


USMCR retired
SDFD retired
FEMA US&R TF8

Re: Generator fan wiring

Reply #13 –
Quote from: red tractor –
In looking at your drawing again looks like someone hooked the ground for the hour meter to the 10 amp circuit breaker and the black wire to the motor to the hour meter. The black wire should go to the 10 amp circuit breaker p.utting 120 volts to the fan motor and then the ground to the hour meter which appears to get its 12 volts from the relay on the side of the control box

The two way correction is the most simple solution.  It would put the 10A CB into the 120v circuit and the hour meter on the 12v.  Before I cut the zip ties, the connectors would not reach the correct contact.  Someone, for some reason, switched wires then tidied everything up with the zip ties.  The black and white wires could also have been reversed, but Brett said his 10A CB was connected to the black wire.  I've got a call into Jeff Jones at Power Tech to verify.  In an earlier call, he said that Power Tech did not put the 10A CB in.  James at FT said they didn't do either.  Your summary, Ron, was very helpful.  Thank you.
2000 U320 mid entry  #5688
2006 Jeep Liberty


USMCR retired
SDFD retired
FEMA US&R TF8

Re: Generator fan wiring

Reply #14 –
Good ending!  I made the suggested changes and everything works.  I re-did the drawing to include only the 120v wiring.  Hopefully, this will  help someone down the road.
I really appreciate all the help, especially from those that stuck with me through this "adventure".  I learned a lot.
2000 U320 mid entry  #5688
2006 Jeep Liberty


USMCR retired
SDFD retired
FEMA US&R TF8

Re: Generator fan wiring

Reply #15 –
I am glad you got it going.
previous 1984 35 ft ORED 250 HP 3208 Cat       
previous 1998 40 ft U295 CAI 325 hp Cummins
previous 2003 40 Ft u320 build #6140 450 Cummins M11.                                                         
1999 Mazda Miata
Ron, Nancy, Tipper the cat, Max The dog
1997 U 270 36 ft build number 5174 8.3 Cummins

Re: Generator fan wiring

Reply #16 –
Great job Sven, gotta be a relief.
Richard & Betty Bark & Keiko our Golden Doodle
2003 U320T 3820 PBDS
Build # 6215
MC # 16926
2016 Chevrolet Colorado 4X4 diesel
 

Re: Generator fan wiring

Reply #17 –
The help I got here probably saved me $1000+ and three weeks waiting for an appointment.  Can't be more appreciative, especially to those who "stayed with it". 
2000 U320 mid entry  #5688
2006 Jeep Liberty


USMCR retired
SDFD retired
FEMA US&R TF8