Coleman AC issues - One fan speed on cool

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Jay & Jazz

Well-known member
Joined
Aug 30, 2011
Posts
52
Location
Massachusetts
Hi All:
I posted on this about 3 years ago and this year decided to try and fix it again.

The AC works on low speed only (well i assume it's low) if i switch it to high it stops until i put it back on low. The fan only mode does not work at all on high or low speed. I thought a few years ago that it was the thermostat and we replaced it and when tested found it really didn't fix it we decided to let it be, but the last couple long hot road trips peaked my interest in fixing it.

The one speed is cool but come those hot humid days it will be tough to keep up so would like it to work properly.

Here is what I have done:

1. Replaced all three capacitors up on the roof (one at a time with testing in between)
2. Replaced the fan motor
3. Replaced the relay switch just above the capacitors on the roof (i think it's the start relay without going back to my notes?)
4. Replaced the high fan relay inside the RV in the roof assembly
5. Of course i checked all wire connections to be sure they were tight on all the wires I could access easily.

SO we are stumped?!?!?!

Help!

Thanks in advance.

94 Tioga Class C
Believe it to be original AC i think 7300 series as the label is worn off on the unit.

 

Triple Slide Jayco

Well-known member
Joined
Mar 17, 2017
Posts
357
I'd drive it to a heating and cooling shop in town and have a guy come outside and ask/show them. The wiring is very similar to a houses furnace and thermostat. It sounds like a wiring issue at the thermostat.

As an FYI, if you call a heating and cooling guy to your home and ask him to have the furnace blower motor turned on high, he just moves a wire from one spot to another to put it on high mode. This is similar to your issue, I believe.
 

Jay & Jazz

Well-known member
Joined
Aug 30, 2011
Posts
52
Location
Massachusetts
Triple Slide Jayco said:
I'd drive it to a heating and cooling shop in town and have a guy come outside and ask/show them. The wiring is very similar to a houses furnace and thermostat. It sounds like a wiring issue at the thermostat.

As an FYI, if you call a heating and cooling guy to your home and ask him to have the furnace blower motor turned on high, he just moves a wire from one spot to another to put it on high mode. This is similar to your issue, I believe.

Thanks. I will do some testing of the wires as soon as i have more time.
 
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