I have a unusual problem it seems. when I have the air running in the "auto" position on thermostat, it works fine, that is until I switch on a overhead 12 volt light, then the air just kicks off. It will come back on in about 2-3 minutes even with the light or lights still on. I have checked the converter with my meter, reading is 13-13 1/2 on DC coming in from battery. 11 volts on all dc fuses. on the AC side of converter, reading is 119 at all breakers. Reading at any outlets are 119-120, Reading at a 12 volt overhead light with battery disconnected is 10 volts, and coach connected to AC. But with the stat set with the "on" mode I can turn on all lights without affecting the air conditioner. Of course in the "on" mode I am actually by-passing the stat, in this mode the fan runs all time but the unit will cycle on and off (just like they did before wall stats)I don't have the knowledge to check out the stat (Coleman mach 1) but it seems to me that it could be in the stat, enough voltage drop when a light turns on to kick the air off, of course after 2-3 minutes it comes back on. Any suggestions, advise or any ideas please? In all my 38 years of rving and 12 years of that fulltiming I have never heard or ran into this!!

You need to correct the 11 volts in the DC side. There must be a loose or corroded connection.Thermostat in "ON" position only turns on the fan and not the compressor and fan.

You have a 12V DC problem... you need the 13V you are reading on all fuses and lights, not 11. Once you solve the 12V problem your AC will work just fine.

Could be a ground problem on the 12 v side.

thanks fellows for the suggestions. I will check the ground, Since I have over 13 volts coming in, then it is in the dc converter . will check the grounds again.

13 volts coming in and 11 volts on fuses doesn't make too much sense. Are you using the same ground for readings?Battery should go to the 12 volt DC distribution panel and the converter goes to the 12 volt DC panel.Disconnect from shore power, then follow the 12 volts DC from the battery.Or disconnect battery and follow 12 volts DC from the converter.Cycling would indicate right off a 12 volt DC circuit breaker tripping and resetting.

Scratching my head on this | Good Sam Community

12 Replies

enblethen
Nomad
Jul 30, 2015
Thanks for the update!
tommy64
Explorer
Jul 30, 2015
I had to replace the converter, that solved the problem
Fulltimers
Explorer
Jul 24, 2015
haddy1 wrote:
Does that 12 volt overhead light happen to be fluorescent? I had one that had a bad filter (capacitor) that caused problems with my thermostat and tank monitors. If the overhead lights were on, all tanks would read full and the fan on the AC wouldn't turn off.
My Brother in law had a florescent light that would turn his microwave on and off.
haddy1
Explorer
Jul 23, 2015
Does that 12 volt overhead light happen to be fluorescent? I had one that had a bad filter (capacitor) that caused problems with my thermostat and tank monitors. If the overhead lights were on, all tanks would read full and the fan on the AC wouldn't turn off.
enblethen
Nomad
Jul 23, 2015
Did you verify that the converter is getting 120 volts AC input?
Did you verify that the converter has no 12 volts DC output?
Make and model of the converter?
make sure you get a multi-stage lower section replacement.
tommy64
Explorer
Jul 23, 2015
enblethen, now it makes sense, the converter is bad, going to replace the bottom part. thanks for the education
MrWizard
Moderator
Jul 23, 2015
you are not the first

second thread in 30 days with the exact same problem
enblethen
Nomad
Jul 23, 2015
13 volts coming in and 11 volts on fuses doesn't make too much sense.
Are you using the same ground for readings?
Battery should go to the 12 volt DC distribution panel and the converter goes to the 12 volt DC panel.
Disconnect from shore power, then follow the 12 volts DC from the battery.
Or disconnect battery and follow 12 volts DC from the converter.
Cycling would indicate right off a 12 volt DC circuit breaker tripping and resetting.
tommy64
Explorer
Jul 23, 2015
thanks fellows for the suggestions. I will check the ground, Since I have over 13 volts coming in, then it is in the dc converter . will check the grounds again.
Ozlander
Explorer
Jul 23, 2015
Could be a ground problem on the 12 v side.