In this guide, we’re going to dive into a common problem with Coleman-Mach air conditioners, focusing specifically on issues with the compressor not working. If you own a motorhome like the Integra 27u, Jayco, or a similar RV that uses these air conditioners, this step-by-step troubleshooting guide could be a big help. The video this article is based on details a common wiring problem that can prevent the compressor from functioning correctly.
The Problem: Fan Works, but the Compressor Doesn’t Kick In
The situation begins with an air conditioning unit where the fan works fine, but when switched from “fan” to “cool,” nothing happens — no cool air, no sound of the compressor kicking in. This is the issue we ran into with our front A/C unit. The rear A/C unit worked perfectly, but the front one had problems. After exhausting all obvious checks (connections, fan condition, etc.), we discovered the real issue: no power was reaching the compressor.
Diagnosis and Initial Steps
We initially took the RV to a dealership, and thanks to a skilled technician at Valley RV, we found the root of the problem. The wiring inside the A/C unit had some issues, specifically involving misplaced or incorrectly connected wires.
Steps to Follow:
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Identify the Wires: The technician explained that the Coleman-Mach units use Wago connectors, which are small and difficult to work with. Inside our unit, several wires were not properly connected. These misplaced wires were the source of our compressor problems.
Here’s the wire situation:
- Two extra wires did not need to be connected, so they were tucked back into the wall.
- The problematic wire connection involved the red and yellow wires:
- The red wire powered the heat pump.
- The yellow wire powered the compressor.
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Correct the Wiring: The red wire had no function in this case because it was supposed to power the heat pump, which wasn’t relevant for our setup. Once we disconnected the red wire and plugged in the yellow wire, everything started working. The compressor immediately kicked in, and the A/C unit functioned correctly.
Wire Details
To give you a better idea of the wiring inside the unit, here’s what we found:
- A bundle of brown cables containing:
- Red and white wires (one thick, one thin).
- Two green wires.
- Yellow and yellow/blue wires.
- A thicker white wire.
- A red/white striped wire.
It’s important to differentiate between the two red wires: one is red with a white stripe, and the other is solid red.
Key Fix:
- Unplug the red wire (heat pump).
- Plug the yellow wire into its place (compressor).
After this, the A/C started functioning normally.
Additional Tips and Considerations
Be Gentle with the Wiring Panel:
During troubleshooting, be cautious with the wall panel covering the wires. The panel is made of thin material (essentially a covered Luan), and repeated use could wear out the screw holes. Instead of drilling new holes, consider using sticky Velcro on the back of the panel to keep it securely in place but easily accessible for future maintenance.
Testing the Fix:
Once you’ve made the adjustments, test the A/C by switching from fan to cool:
- Keep the fan on a low setting so you can hear when the compressor kicks in.
- Switch the unit to “cool” and listen for the compressor to start.
This simple wiring fix can resolve issues where the fan works, but the compressor doesn’t.
Conclusion
Finding solutions for air conditioning problems in an RV can be frustrating, especially when service appointments are hard to get. But with some careful troubleshooting, you can fix issues like a non-functioning compressor yourself. If you’re experiencing this problem with your Coleman-Mach A/C unit, check your wiring connections — particularly the red and yellow wires.
Hopefully, this guide has provided you with enough detail to get your A/C working again. If you’ve tried everything and still can’t fix the problem, it might be time to schedule a professional service visit, but be prepared for delays as RV service appointments can be tough to get.
Good luck, and happy travels!
