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Topic: 12V Dash Circuit Breaker Electrical Problem (Read 885 times) previous topic - next topic

12V Dash Circuit Breaker Electrical Problem

You guys might get tired of me soon ;)  In my 1999 U320 42' I just finished replacing the coolant, heater hoses and the couplers on the radiator/transmission cooler.  Oh dear what a bear of a job.  Those hoses do NOT want to come off.  I even have the correct picks to break up the seal.  Anyway....  It holds coolant, warmed up to 180 and held with the fan coming on. Ok :)

But there was a clicking, light dimming, and volt meter drop.  I narrowed it to circuit number 12 on the passenger side dash breaker panel.  This is a 12v breaker.  My manuals seem to be missing the 12v dash wiring so I do not know what this breaker is for.  When it engages I feel something near the step also click but it pops immediately - definitely a dead short.  Does anyone know what this circuit is and does anyone have these diagrams as well plumbing diagrams for a U320 42' as well?

And of course chassis a/c blew cold, then got warm and I found the fan not running on the condensor,  so now I have to figure out relay or fan motor.  At least that's an easy job.  Thanks in advance for any help with that breaker.

Re: 12V Dash Circuit Breaker Electrical Problem

Reply #1 –
If you can identify the wire number going to the breaker, perhaps I can check my documentation and find out what it supplies.    The wire numbers are printed onto the wire every few inches.

Dave VanAmburg
David VanAmburg
'99 U320 42ft

Re: 12V Dash Circuit Breaker Electrical Problem

Reply #2 –
The condenser fan on my 2000 was on the same breaker as the ECM.  I split them after turning on the AC stalled the coach with a short in the condenser fan.  Lots of times that fan dies as it is subjected to lots of road messes.
2025 Wanderbox Outpost 32 on F600 Expedition Motorhome
2015 Born Free Royal Splendor on Ford 550 nonslide version  for sale
Former Coaches  covering. 360,000 miles
1999 34 U270
2000 36 U320
2001 42' double slide U320
2018 Jeep Rubicon

Re: 12V Dash Circuit Breaker Electrical Problem

Reply #3 –
The condenser fan has failed to run a couple of times on our 1997 coach. First one was easy. A connecter to a pressure switch on the refrigerant line near the compressor had loosened. Pushing it firmly onto the switch fixed the problem. The next failure was with a cube relay mounted near the isolator. The cube is exposed to weather and the plug pins had corroded through. I replace two cube relays and sockets in that area, and the condenser fan works well.
J D Stevens
1997 U295 CAI 36' Build #5085
2002 Subaru Outback
Motorcade 16869
Bellville, TX

Re: 12V Dash Circuit Breaker Electrical Problem

Reply #4 –
Quote from: wamu1david –
If you can identify the wire number going to the breaker, perhaps I can check my documentation and find out what it supplies.    The wire numbers are printed onto the wire every few inches.

Dave VanAmburg

It's a white wire and it says COMMON 60 on it.  Underneath the breaker 60 WH is printed as well.

Re: 12V Dash Circuit Breaker Electrical Problem

Reply #5 –
Yeah the AC wasn't working when we bought it.  The tech replaced the breakers but not the relays but I know all too well about those bosch relays.  I figured they were at least part of the issue but they did demonstrate a working a/c.  It just stops working once it's warmed up ;)

For reference, I was PM'd the answer to the wire 60 inquiry which is the TV disconnect when the ignition switch is on.  The coil must be fried.  So for me this is an easy solution - disconnect the wire ;)

Re: 12V Dash Circuit Breaker Electrical Problem

Reply #6 –
My drawing shows that the #12 beaker has two wires coming off it.  60 WH supplies the TV relay (interupts TV power supply when ignition is on).      C11 WH supplies the fold down step.    Should be fairly straight forward to disconnect each wire and see if your problem goes away and then track down the offending relay.    Hope this helps.

Dave VanAmburg
David VanAmburg
'99 U320 42ft

Re: 12V Dash Circuit Breaker Electrical Problem

Reply #7 –
Well that explains why I feel a noise underneath me for a split second before the breaker trips.  Certainly the tv disconnect relay is to blame.  I doubt the step would be making a noise if it tripped.  I'll get to work on it once all this rain stops ;)

Re: 12V Dash Circuit Breaker Electrical Problem

Reply #8 –
Looks like our condenser fan motor needs replaced. When I turn it on (engine off, key on, ac on) it runs for about 10 minutes, then starts slowing down making bearing noise and then stops.  After that about a minute later you can hear the resettable breaker by the battery isolator pop.  I swapped out the relay and breaker to narrow it down but it looks like it's definitely the motor. 

Anyone have a part number for the condensor fan motor?  I see it's like $200 from FOT but I feel like a simple 12v motor could potentially be had cheaper.

Re: 12V Dash Circuit Breaker Electrical Problem

Reply #9 –
That motor is operating in a harsh environment.  I wouldn't go cheap.
Regards,
Brett

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

Re: 12V Dash Circuit Breaker Electrical Problem

Reply #10 –
Quote from: piku –
Looks like our condenser fan motor needs replaced. When I turn it on (engine off, key on, ac on) it runs for about 10 minutes, then starts slowing down making bearing noise and then stops.  After that about a minute later you can hear the resettable breaker by the battery isolator pop.  I swapped out the relay and breaker to narrow it down but it looks like it's definitely the motor. 

Anyone have a part number for the condensor fan motor?  I see it's like $200 from FOT but I feel like a simple 12v motor could potentially be had cheaper.

Pull the motor and then take it to Autozone/O'Reilly/NAPA for a cross reference. Also may be possible to just use the part number on it and then call around.  It is very likely to be a common motor used by many domestic cars/trucks. Should be inexpensive new or super cheap from a pick and pull yard. They normally have a very long life unless mounted where they get a lot of road spray. Here is a page to look at once you have it off: auto ac condenser motor | eBay

Pierce
Pierce and Gaylie Stewart
'93 U300/36 WTBI
Detroit 6V-92TA Jake
1140 watts on the roof
SBFD (ret)

Re: 12V Dash Circuit Breaker Electrical Problem

Reply #11 –
Piku,
Take a look through all your many Foretravel instruction manuals.  You should several pages of wiring diagrams in the back of one of those manual.  It is invaluable in these situations!!
1994 U225
build #4514

Re: 12V Dash Circuit Breaker Electrical Problem

Reply #12 –
Man, if they're that expensive on ebay I might as well call FOT.  They're not making anything on them
 

Re: 12V Dash Circuit Breaker Electrical Problem

Reply #13 –
Piku, Take a shot at reviving that DC motor.  Two things to try.
1.  Remove motor and stand on end, drizzle a good quality penetrating oil down the shaft towards the bushings.  Do this for  2 to 3 days, oil will loosen up bushing and it may run for years then.
2. Remove motor, drill a small hole < 1/16 in end cap of motor where bushing is, drizzle in good quality penetrating oil;  See if that works.
Don't use  anything like 3 in one oil, it will gobber up.  Singer Sewing machines have a good oil.
Good luck.
Gary B