That could be the light sensor in the dash, the control relay or a fault in the body control module. Testing the auto relay is simple, it is the same relay as the DRL's so just swap them and if the DRL's stop working but the auto on works, replace the bad relay. They are both in the under hood block on the drivers side.
If swapping the relays doesn't work then you will need to test if the sensor is bad. The easiest way to do that is with a scan tool that can read the body module and tell you if the lights are being turned on by the automatic system. It can also tell you if the sensor is bad as it will set one of two codes if it has shorted or opened. The other method would be to just replace the sensor as getting to it just to test it is a bit of work as it requires the dash pad be removed to get to it and takes about 2.5 hours. It is the small knob like item on top of the dash.
However if it isn't the issue then it is likely the body control module. Replacing that requires that it be programmed to your vehicle as well.
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Friday, July 10th, 2020 AT 6:12 PM
