AIR CONDIONING INOP

[champcar50]

THE FRONT ROOF A C ON MY 1983 NEWELL IS INOPERATIVE. iT WAS THIS WAY WHEN WE PURCHASED THE COACH. I HAVE CHECKED AT THE AC UNIT AND THERE IS NO POWER THERE. I CHECKED AT THE BREAKER PANEL AND ALL OF THE BREAKERS HAVE 120 VAC ON THEM. SO I MUST HAVE A OPEN SOMEWHERE BETWEEN THE AC UNIT AND THE BREAKER BOX. i WONDER HOW THE WIRES GET FROM THE BREAKER TO THE AC UNIT? DO THEY RUN OVERHEAD OR DO THEY RUN UNDER THE FLOOR THROUGH THE BAYS? ARE THEY IN CONDUIT? THERE MUST BE A SPLICE SOMEWHERE? THE BREAKERS ARE NOT MARKED I ASSUME THE TWO AC UNITS EACH HAVE THEIR OWN BREAKER? THE REAR UNIT WORKS GOOD. ANY HELP IS APPRECIATED.
THANKS
jACK

[Richard and Rhonda]

Check the starter capacitor for the compressor motor. If the cap is bad, and you checked downstream, i.e. just at the comressor, you wouldn't see voltage.

[champcar50]

Hi Richard
Thanks for your suggestion. I checked for voltage where the romax is wire nuted to the ac wires in the box at the ac
thanks
Jack

[Richard and Rhonda]

Cool.

Well, that's just downright strange. You said you had voltage out of the breaker, right? But no voltage at the other end of the wire?

I think this next step would already confirm what you suspect. If you disconnect the wiring at the breaker, and disconnect the wiring at the A/C, you could temporarily tie the wiring together at the A/C and check the hot and neutral for continuity by ohming it.

I would do this before I started disassembling the coach to run new wire. If the symptoms are true, either there is a break in the wire, and the wire runs through a junction box and a wire nut has come loose.



Whoa, wait a minute. What tells the A/C to come on? When you said roof unit it threw me. I have basement air but had a similar problem. On mine the thermostat "talked" to a printed circuit board. The circuit board had a relay that "made" to send power to the compressor unit. That relay was not making, and therefore no power to the compressor unit. I confirmed this by direct wiring the in and out power wires that went through the relay. I bought a new relay and installed it on the board. Voila !! A/C

What tells the A/C to come on? Is it a switch on the unit itself, or a wall mounted thermostat? I am sorry I am not familiar with your setup.

[champcar50]

More investigation has revealed that the white wire is common with the ground in the breaker box. The black wire is open somewhere between the breaker box and the ac unit. I have found which breaker the ac unit is on so now I am trying to trace the wire to the front of the coach. At the ac unit the wire comes from the passenger side of the coach. Do you suppose it comes across the coach in the roof at the rear and then travels in the wire chase down the passenger side? Is there some sort of a tone generator and an amplifier I can get to trace the wire?
Thanks for your help
Jack

[fulltiming]

Jack, you can pick up a tone injector and signal tracer, also called tone and probe, at major home improvement stores or a store such as Sears. I have 120 volt lines running both in the overhead raceways and in the floor raceways. Since I have basement airs, the wires are run in the floor raceways. It is likely that your roof airs would be run through the overhead raceway, likely on the same side of the coach as the power panel.

[Richard and Rhonda]

Jack,

Before you start tearing the coach apart looking for this wire. How does the A/C know to come on. Do you turn a knob mounted directly on the unit, or is there a wall thermostat? If you have a wall thermostat, then 120VAC definitely does not travel through the thermostat. The thermostat triggers a relay somewhere that turns on the juice to the A/C. Your black wire open is consistent with this. The white wire is used for neutral as you know, and the black for hot. Any relays or on/off mechanism is always used on the black.

If you have a thermostat, trace the wiring coming out of it.

As I have thought more about this, the black wire HAS to go through some sort of switch, because if the black wire to the compressor was hot all the time then the A/C would run all the time. Gotta find that switching circuit I think.

[encantotom]

on my 90 with roof airs, the romex for the ac runs directly from the breaker box up the wall and down the corner wire chases directly to the area where the ac is mounted and then juts over in the headliner to the ac. so, the hardest part in mine would be in the headliner, but if it isnt secured, you could use the old wire to pull the new one.

havng said all that, there is nothing that in mine would cause the romex to break on one of the lines. it is very strange that it would be open. i assume since you checked at the breaker that it didnt simply come out of the breaker (the copper wire).

mine are not tied to thermostats, so quite simple.

tom

[champcar50]

Update on my ac adventure. I have ran a new 12/2 romax from the breaker box to the ac line across the top of the coach. I think it will be ok once I get it connected to the breaker. I pulled out the stranded wire that was previously connected to the ac. It went to a grey metal box about 3x4x3 located in the cabinet above the windshield on the drivers side. When I took the cover off this box it has a double contact set of points in it. There are several wires that are conected to this including the black wire that previousley went to the ac. Most of the wires are 14 gauge or smaller. Any ideas what its purpose is? I did not find any ac voltage in it. Also according to the legend for the circuit breakers both ac units are on the same side of the generator. Is this normal?
Thanks
Jack

[Richard and Rhonda]

Jack,

Any updates? I am guessing that your real problem lies in the fact that you said the wiring went through a set of contacts and you did not have power at the contacts. What triggers those contacts?

Also, another bizarre scenario came to me. What kind of service are you plugged into right now?

If it's fifty amp, you should have power to both legs of 120, but if you are plugged into 30 or 20 amp service and depending on your cheater cord setup, you may only have 120 to one leg.

Have you checked the power situation with the genny running?

[HoosierDaddy]

My '78 has a switch just above the driver side window. It's a regular ol' wall light switch......it controls power to the front A/C

[chockwald]

HoosierDaddy.....my 1982 has the same switch. Enables driver to turn the front A/C on, or off while driving......I wonder if Champcar50 has the same switch in his '93?

[fulltiming]

Well, it looks like Dean and Clarke may likely have the answer. I would not have thought of that since the Series 2000's didn't have such a switch. Good catch gentlemen.

That would make sense if the driver's switch is off that power to the front AC would be interrupted.

This forum gets better every day!!