Butch39

Dash heater/AC motor problem

9 posts in this topic

Have a 2003 Holiday Rambler Vacationer and the dash heater/ac motor will not run now and then. The no run problem is not consistant, in other words the problem is present now and then. When the motor will not run the light in the heater/ac/temperature panel, on the dash will illuminate if the fan speed switch is on. If one is to turn the heat/ac/defroster control switch on/off quickly, it will sometimes start running. Most times it starts when it wants to. Most times if you start it when you first start out, as if using the ac, it will run until you shut it off or shut it down, as if you were re-fueling the coach. If you just leave it alone, in the "on" position, the motor will start running somewhere down the road. My thoughts on the "no-run" situation is; that the bush(es), within the motor, are not making good contact with the motor armature, as if a bush(es) failure and the circuit is going to ground through the panel light bulb. I have a strong automotive/electric background, and have worked a number of years, years ago, as a mechanic of cars, trucks, and buses. Just wondering if anyone has had this same problem, your experiences may be the answer to my problem......thanks.......

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Hi Butch,

The brushes could be the problem, along with the switch, ground wire, connections, etc. It is time to get the meter out and starting with the easiest part to access, take readings. If you can get the failure to occur and be able to take the measurements, that would help. I had a similar problem back in the 1980's. However, my problem was a hard failure. It was the dash switch. I hope you find the problem before it drives you nuts. Good luck.

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Hi Butch,

The brushes could be the problem, along with the switch, ground wire, connections, etc. It is time to get the meter out and starting with the easiest part to access, take readings. If you can get the failure to occur and be able to take the measurements, that would help. I had a similar problem back in the 1980's. However, my problem was a hard failure. It was the dash switch. I hope you find the problem before it drives you nuts. Good luck.

All good info and X2 for me. In many cases like this in other vehicles it usually turns out to be the switch. For the amount of use the motor gets over a period of time compared to a daily driven car I would guess it isn't the motor brushes but I wouldn't rule it out either.

Good luck.

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Good advice.

Usually the motor is easier to access than the back of the controls. Go to whichever is easier to access. Measure voltage between hot wire to motor and the ground wire to motor. If you don't have 12+ VDC with switch on and ignition on, measure from that hot to known good ground to rule out the ground wire.

The other thing you can do is put 12 VDC positive to the motor hot lead when the fan is not working. If it works then, the switch is the likely culprit.

Brett Wolfe

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Thank you all for your response to our problem, and if I can get it to screw up in the driveway, I will try your posted responses as to testing the circuits....... thanks again.............

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Butch39, I had the same problem on my previous coach. It was the postive wire connection to the post on the blower motor. It was loose. I crimped the connector a little bit where it made good firm contact. Wala! no more problem. Hopes this helps.

Herman

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Just an update about the a/c, heater motor problem. After some testing, I found that the problem was the motor, infact it was the end bearing. As the bearing is oilite, (impregnated oil/bronze type), I slowly added 3in1 oil to bearing while the motor was running. The oil was absorbed by the bearing material and have not had a problem with it since early summer. My only regret is that I did not drill a small lubrication hole in the motor case, while it was removed, so that I may add a drop or two of oil now and then. Can not be drilled in place and is a real pain to remove. Atleast at 71, it's tough.......

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Good job.

I recommend a light viscosity non-detergent oil such as sewing machine oil as preferable to 3-1 oil. 3-1 tends to get more viscous with time.

Brett

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Good job.

I recommend a light viscosity non-detergent oil such as sewing machine oil as preferable to 3-1 oil. 3-1 tends to get more viscous with time.

Brett

Thanks for the suggestion on the sewing machine oil, never thought of that, I'll have to borrow some from the wife for the next bearing lube job. Thanks again Brett.

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