Hello All,
Living in the Barth going on two years now. Just had one of our coleman roof units go out on our 88 regal. Appears to be fan only. I think compressor is OK. Anyone with steadfast knowledge on fixing the fan as opposed to replacing it(around $180.00 at camping world)?

Also when we're running our 12 volt appliances at night we have had problems with lights dimming intermittantly. The Koolmatic ceiling exhaust fan also slows. Sound like converter?
Thanks,
Jack

Jack have you removed the AC cover to check the fan? It might just be stuck spin it by hand and give the oil cups a little oil might help.

Ralph

quote:

Also when we're running our 12 volt appliances at night we have had problems with lights dimming intermittantly. The Koolmatic ceiling exhaust fan also slows. Sound like converter?
Thanks,
Jack

Converters come in two flavors - single-output and dual-output.

The former is connected to the battery directly, and 12V power always comes from the battery, which the converter is charging.

The older style dual-output connects to the house 12 V circuits directly, with a separate circuit to charge the battery. When 120 V is available, the converter disconnects the battery (by way of a cutover relay) to the house 12 V and supplies it directly. Based on the age, the dual-output is probably what you have.

Assuming you have no high-load 12 V appliances (coffee pot or cup warmer that would put an occasional heavy load on the 12 V circuits when the thermostat kicks in),

You may have:

a) A falty converter - possibly the charger circuit or a failing cutover relay.

b) Fluctuating 120 V

c) A bad house battery/ies - the converter 12V sags when the separate charger kicks in.

a) and c) can be tested by disconnecting the house battery/ies. If the fluctuations disappear, it's either the charging circuit or the battery. If they persist, either the cutover relay is failing, you have a failing converter, or 120 V is fluctuating. If the 12 V lights don't come on, then you have a single-output converter, and the diagnostics are a bit more involved...

I would recommend that every RV owner have a Kill a Watt and a digital 12v DC voltmeter. When you are plugged in at a park power pole, there are voltage issues, and when you are dry camping and using the genset, there are frequency issues. The Kill a Watt addresses both AC power issues at a reasonable price.

And the DC voltmeter is necessary to keep track of what the battery and its charging sources are doing. DO NOT buy the junk Chinese cigarette lighter plug in meter that CW sells.
If anyone is interested, a really good self-powered digital meter, the Lascar 1200 is available from Allied electronics. It is a two wire hookup, hot and ground, and mounts with one stud. It can also be attached to a cigarette lighter plug with epoxy or shoe goo to make a handy-dandy portable tester for all your vehicles. I seem to remember that Electronic Goldmine had a real good price on them, too. I could not live without mine.



A digital multimeter will do all of this except frequency, so if you are never on genset power, that is a cheap way. Park frequency is never an issue, just voltage. Death, taxes and line frequency are the only sure things in this world.

Does your fan motor turn by hand? If it does, does the motor hum when trying to operate? You might feel the vibration or have to listen with your ear right on it to tell. Does it get warm? Does it have power going to it? Can you trace power from the speed switch? My only fan motor failure was from chronic low voltage in a park. I was surprised, as I would expect the harder-working compressor motor to fail first. It was an easy replacement, but had to wait for the PB Blaster to work. Still had to cut the shaft and drive the remains out of the fan hub to reuse the fan.

Anyone know much about Toyota charging systems?

Also, the fan motor is probably a synchronous, but the compressor may have run and start capacitors. If it was a failure to run after sitting, it could be those, or it could even be the contactor from the thermostat to the 120V.

And bill h is right on - get a reliable, accurate multimeter and another thing I'd suggest is a plug-in 120V meter...so you can monitor line voltage. I had to test four at my RV dealer before I found one accurate (tested against one of my better multimeters).

quote:

Anyone know much about Toyota charging systems?

I know a little - I had a Celica and have a Lexus...so far they seem to be fairly straightforward, but I'm a close friend of probably the best independent Toyota shop owner in Florida.

Thanks Ralph,
I'll give it a whirl.
Jack

Thanks Bill and Rusty for your helpful input as well.
Jack

Regarding the AC, compressor kicks on but not the fan so its definitely a fan problem. Yes the motor hums with power on and makes a few revolutions. No smoking though. The shaft seem to spin freely by hand without power. With the power on the motor trys but just does not want to turn. Can't seem to locate any oil ports or places to put oil. Where to put the oil if no visible ports?
Also exporing the possibility of a decent used motor. It's a Westinghouse 1/4 hp if any one has any leads. Guess I'll pull it out and try to fix it myself otherwise it looks as though there are a few elctric motor serviceand repair shops here in L.A. Thanks.
Jack

Is there a capacitor in the fan motor circuit? If there is, you can test it (sort of) with an analog ohmmeter, or have it tested at a shop. Prolly 5 or 7 mfd. Might be marked.

Are any connections loose or corroded?

Jack my colemans are 1976 models , may be different than yours but the motor has a plastic plug above each end of the motor which has to be removed for oiling. My units also has a start capictor for the fan , located in a metal box which the motor wires run into close to the motor.
If the motor turns freely and hums it just migt be the start cap like Bill mentioned.

Ralph

I haven't been in a roof air fan motor for quite a while, but there might be a centrifugal switch thingy inside, at the end where the wires enter. Sometimes they get sticky or the contacts need a little burnishing or planishing.

I got some SAE 20 non detergent oil today and put it in an oil can with a nice long spout. I injected the oil into any hole the spout would fit into. The fan ran strong for about 3 minutes on two separate occasions then quit again but only on high setting, not on low. Does that sound like a capacitor or centrifugal switch thingy. Or perhaps this ole fans just about had it. Thanks again gentlemen.

Jack

It sounds most like a run capacitor, or a problem with the switch. The centrifugal switch (if there is one, which I doubt) would cut out at low RPM.

The fan has wiring for 3 speeds, each one increasing the amperage for low, medium, and high speeds. The wiring can burn out and usually when this happens-it's time for a new fan motor unless you can deal with the speeds that you have left.