
AC Not Cold and Bad Smell – Jeep Grand Cherokee 2020
The air conditioning works well at highway speeds but becomes warm in stop-and-go traffic, accompanied by a bad smell. This suggests a refrigerant issue (likely low charge) combined with moisture or mold in the evaporator causing the odor.
Diagnosis Details
Possible Causes
Low refrigerant charge due to a small leak (e.g., at compressor seal, condenser, or lines). At highway speeds, the compressor runs more efficiently, but at idle it cannot maintain cooling.
Clogged or dirty cabin air filter restricting airflow, causing the evaporator to freeze and then thaw, producing a musty smell.
Faulty AC compressor clutch or control valve not engaging properly at low RPM.
Related OBD-II Codes
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What You Should Do
Check refrigerant pressure with a manifold gauge set.
If low, perform a leak test (UV dye or electronic leak detector).
Replace cabin air filter if dirty.
Clean evaporator with a foaming cleaner if mold is present.
If compressor clutch fails, replace compressor.
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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.


