Q: Resistors on AC stay on - 2002 Mercedes-Benz

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My air conditioner only worked periodically in my car, so I replaced the cabin air filter and removed leaves and dirt from the blower motor. It didn’t help at all. So I bought a new blower motor resistor and the air conditioner worked on all the settings. But when I took the key out of the ignition the fan stayed on and wouldn’t turn off. I replaced this resistor with a new one and it still did the same thing. Do you know what’s wrong? Could it be that both resistors were no good?

Hi there. If the fan is staying on when the vehicle is turned off, then it may have a bad connector at the resistor. It is common for these resistor connectors to melt and cause this to occur. If the connection is fine, then it may have a relay that is sticking but that is not as common. I typically do a circuit test with a voltage meter to see where the problem lies. If you are going to have this fixed, consider YourMechanic, as a certified mechanic can come to your home or office to inspect the AC problem and guide you with a repair.

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