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Topic: Mystery noise (Read 947 times) previous topic - next topic

Mystery noise

When everything is shut off except my salesmen sw. Is on, I get a noise that sounds like a small motor. All at fans etc. Are shut off. Any thought on what is might be?  It's a 95 u320.
1995 U320 40', 2013 chevy sonic toad, my real love are corvettes have owned 30

Re: Mystery noise

Reply #1 –
My Prosine battery charger has a cooling fan.

Rich
Rich and Peggy Bowman
2002 U270 3610 WTFS, build #5939--"Freedom"
2022 Jeep Grand Cherokee Summit 4xe
SMI AirForceOne brake system
PakCanoe 15

Re: Mystery noise

Reply #2 –
12v air compressor in basement?? 
John and Stacey Smith
Motorcade NO: 11973
1997 U295 CSGI 40'..Build No. 5036     
920 Watts on the roof..CAT Power w/fuel Inj. Programmer
2021 GMC Sierra AT4 1500
EX..2015 Jeep Wrangler Sahara
Ex 1990 U280 RSAI 36'..Build No. 3638

Re: Mystery noise

Reply #3 –
Guys I don't have a pristine charger and could the 12 v compressor be located under the coach in front of passenger seat under the dash.
1995 U320 40', 2013 chevy sonic toad, my real love are corvettes have owned 30

Re: Mystery noise

Reply #4 –
Vacuum pump for your heater/AC system? It should run for a bit and shut off. If it's leaking it will keep running.
jor
93 225
95 300
97 270
99 320

Re: Mystery noise

Reply #5 –
Not I think you might have hit on it. The noise seems to be coming from that area. How can I access it?
1995 U320 40', 2013 chevy sonic toad, my real love are corvettes have owned 30

Re: Mystery noise

Reply #6 –
Jor I think you might have hit on it. The noise seems to be coming from that area. How can I access it?
1995 U320 40', 2013 chevy sonic toad, my real love are corvettes have owned 30

Re: Mystery noise

Reply #7 –
Should that vacuum pump run when the engine is off? On my coach, which admittedly is quite a bit different, that vacuum pump runs the automotive heating/air conditioning system.

As for finding something that's making noise, just follow your ears. One possible hint would be for you to get as close to it as you can, then have someone else turn the salesman's switch off and see if the sound stops. If it does, you know that it is something on that side of the circuitry. If it doesn't it is something that Foretravel considered important enough to have power no matter what.

Another possibility would to make sure that the two sets of batteries are separated (boost switch off, trik-l-charger disconnected) then disconnect one set of batteries and listen for the noise. If present, reconnect and disconnect the other set. If disconnecting the engine batteries stops the noise then it is something chassis-related. Otherwise it is house-related.

Re: Mystery noise

Reply #8 –
Quote from: Rich Bowman –
My Prosine battery charger has a cooling fan.
As does my 'Truecharge 40', and it took me a while to understand WHAT that sound was. Now, like the lighthouse keeper who slept through the foghorn, if it ever fails, I will say, "what was that?"
1993 U-240 "La Villa Grande"..CAT 3116 w/ Pacbrake PRXB...Allison 3060 6-speed..
Previous: 1983 Airstream 310 turbo diesel, 1979 Airstream 280 turbo diesel
                                      Build # 4297
                                      PNW natives
                      Home base:  'Cactus Hug' (Ajo, Arizona)
                        DW Judy & Chet the wonder dog
                        Full-Timers 'Sailing the asphalt sea'

Re: Mystery noise

Reply #9 –
Yes, most converters, battery chargers and inverter/chargers have muffin fans to keep them cool.  Should be easy to locate and rule in/out.
Brett Wolfe
EX: 1993 U240
Moderator, ForeForum 2001-
Moderator Diesel RV Club 2002-
Moderator, FMCA Forum 2009-2020
Chairman FMCA Technical Advisory Committee 2011-2020

Re: Mystery noise

Reply #10 –
Quote from: wolfe10 –
Yes, most converters, battery chargers and inverter/chargers have muffin fans to keep them cool.  Should be easy to locate and rule in/out.
Another 'sound' that drove me to drink (easy) was Brett had installed muffin fans in the exterior fridge that got me crazy at night before I found the switch!
1993 U-240 "La Villa Grande"..CAT 3116 w/ Pacbrake PRXB...Allison 3060 6-speed..
Previous: 1983 Airstream 310 turbo diesel, 1979 Airstream 280 turbo diesel
                                      Build # 4297
                                      PNW natives
                      Home base:  'Cactus Hug' (Ajo, Arizona)
                        DW Judy & Chet the wonder dog
                        Full-Timers 'Sailing the asphalt sea'

Re: Mystery noise

Reply #11 –
Ya, but they help keep your beer cold when it is over 100 degrees  out and the sun is shining on that side.
Brett Wolfe
EX: 1993 U240
Moderator, ForeForum 2001-
Moderator Diesel RV Club 2002-
Moderator, FMCA Forum 2009-2020
Chairman FMCA Technical Advisory Committee 2011-2020

Re: Mystery noise

Reply #12 –
Guys I agree with you all except my fridge is off no fans. What ever it is is on 12 volts. When I turn my salesmen switch off then the noise stops.  I will start with the vacuum pump if I can find it.
1995 U320 40', 2013 chevy sonic toad, my real love are corvettes have owned 30

Re: Mystery noise

Reply #13 –
Your vacuum pump that powers the dash HVAC should ONLY work with ignition ON.
Brett Wolfe
EX: 1993 U240
Moderator, ForeForum 2001-
Moderator Diesel RV Club 2002-
Moderator, FMCA Forum 2009-2020
Chairman FMCA Technical Advisory Committee 2011-2020

Re: Mystery noise

Reply #14 –
Sounds like you are getting closer. Is the sound louder inside or outside? If outside, you are probably going to have to stick your head up in front of the RF tire, so be sure that you have your safety blocks in place. If you can, raise the coach all the way up, shut off the engine, and install the safety blocks.

If it is louder inside, do you have a fuse/circuit breaker panel in that area? It may be hidden behind a removable trim piece. Remove that, and see if it gets louder. Opening the top of the dash may also make the sound louder.

Don't be surprised if the sound seems to move as you get closer. The thing actually making the noise may be in front of the driver's seat, but the only route for the sound is toward the navigator's seat. Patience is going to be tested, but you ought to find it eventually.

Re: Mystery noise

Reply #15 –
Well it appears that my ac controls which dont work by the way are controlled by little electric motors not vacuum. I will now look at these of which there are three and see if thats the noise problem and also why controls dont work. Thanks everyone.
1995 U320 40', 2013 chevy sonic toad, my real love are corvettes have owned 30

Re: Mystery noise

Reply #16 –
Did you ever locate the source of the noise?  Following.
2001 4010 U320 build #5865 "Bluto-d-Bus" since 09/18
2006 Honda Element ESP Toad
Full timing since 2016 in Western MT
Copilot: Sitka
1975 GMC 260 Avion: sold
 

Re: Mystery noise

Reply #17 –
I won't have a chance to confirm until after christmas, but I am quite sure it one the little motors that controls my dash dampers. I would go to wish everyone a safe and Merry Christmas.
1995 U320 40', 2013 chevy sonic toad, my real love are corvettes have owned 30