Trane AC Not Cooling? Common Causes & How to Fix It

First, the fast checks

If your Trane AC is running but not cooling, start with the five checks that fix most no-cool calls:

1. Thermostat - set to COOL, target below room temp, fresh batteries. On a ComfortLink communicating thermostat, a blank screen can point to a control issue.
2. Air filter - a clogged filter chokes airflow and freezes the coil. Replace it if it's dirty (how to).
3. Breakers - reset the indoor and outdoor breakers once; repeated trips mean call a pro.
4. Outdoor unit - is the fan spinning? Clear debris and confirm the disconnect is in.
5. Frozen coil - ice on the lines means shut the AC off (fan ON) to thaw, then run with a clean filter.

Still warm? Here's what's most likely on a Trane.

The Trane-specific causes we see most

• TXV (thermostatic expansion valve) failure. A known Trane service item - a failing expansion valve restricts refrigerant flow and causes poor cooling even when everything else looks fine. This needs a tech with gauges.
• Failed run capacitor or contactor - the most common no-cool cause on any AC; if the outdoor fan hums but won't spin, this cheap part is usually it.
• ComfortLink communicating board faults on variable-speed XV systems.
• Low refrigerant from a leak - Trane's all-aluminum Spine Fin coils are durable, but when they do leak, cooling drops and you'll often see ice on the lines.

See the full list on our Trane repair page, and our general guide to why an AC stops cooling covers the rest.

When to call a pro

Call a licensed tech if you suspect a TXV or refrigerant issue (anything needing gauges), the coil keeps freezing, the outdoor fan won't run, or the breaker trips repeatedly. The good news: Trane needs repairs less often than most brands - see our Trane brand review.

Trane AC down today? Get matched with a licensed local pro for same-day Trane repair - upfront pricing, no overtime fees.