A/C Not Cold and Bad Smell – Jeep Wrangler 2020
The A/C blows cold on the highway but warms up in traffic, accompanied by a bad smell. This suggests a refrigerant issue (likely low charge) and possible mold or debris in the evaporator case. The smell may be from stagnant moisture or a failing cabin air filter.
Diagnosis Details
Possible Causes
Low refrigerant charge due to a small leak (common in Wranglers with age). Insufficient refrigerant causes the evaporator to freeze at highway speeds, then thaw in traffic, producing a musty smell.
Clogged or dirty cabin air filter restricting airflow, causing the evaporator to ice up and then thaw, leading to odor.
Faulty A/C compressor clutch or expansion valve not regulating refrigerant flow properly, causing intermittent cooling.
Related OBD-II Codes
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What You Should Do
Check refrigerant pressure with a manifold gauge set (low side should be 25-35 psi, high side 150-250 psi at idle).
Inspect cabin air filter and replace if dirty.
If low on refrigerant, perform a leak test (dye or electronic detector) and repair the leak before recharging.
Clean the evaporator drain tube to prevent mold.
If compressor clutch doesn't engage, test clutch coil and relay.
Related Repairs
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Disclaimer: This AI-generated diagnosis is for informational reference only. Always consult a qualified mechanic for an in-person inspection. AutOwner is not responsible for decisions made based on this information.
