RV AC Relay Failure: Causes & Fixes

Contactor stuck or pitted. Clicking but no compressor start.

System context: To understand how RV air conditioners work, see RV AC Not Cooling.

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AI Quick Summary: RV AC relay failure usually indicates:

Relay (contactor) switches 120V to compressor. See AC clicking noise, compressor not turning on, and capacitor failure.

What This Problem Usually Means

The relay (contactor) receives the low-voltage signal from the thermostat and switches 120V to the compressor. A failed relay can click but not pass power, or stick closed. The reader should feel instantly understood. Relay failure often occurs with capacitor failure—both get stressed by repeated start attempts.

The 3 most common causes: (1) Pitted contacts from arcing, (2) Coil failure, (3) Contactor stuck.

Quick Troubleshooting Steps

  1. Step 1 – Capacitor first: Replace capacitor before assuming relay. Capacitor failure often causes relay clicking.
  2. Step 2 – Visual check: Inspect contactor for burned contacts, pitting.
  3. Step 3 – Continuity: When thermostat calls for cool, relay should close. Test with multimeter.

Related Troubleshooting Guides

AC Clicking Noise · AC Clicking But Not Starting · Compressor Not Turning On · Capacitor Failure · RV HVAC Hub

Frequently Asked Questions

What is the RV AC relay?

Contactor that switches 120V to compressor. Receives low-voltage signal from thermostat. Failed = clicking but no compressor start.

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About the Author

Adam Hall — Founder, DecisionGrid

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Updated March 2026 · Reviewed for technical accuracy

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Last updated: March 2026 · Reviewed for technical accuracy

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