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Q: Transmission speed sensor and the internal lights don't work

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The transmission speed sensor is out and the internal lights all don't come on or don't work the brake light only comes on when I have the head lights on and it stays on and the shifter only shifts when the lights are on or I push the bypass button

My car has 107800 miles.
My car has an automatic transmission.

Hi there. According to what you’ve described, there could be a wire harness issue, a ground that has failed, blown fuses, and so on. Check all the fuses and replace any fuses that are blown.

Check relays for a click when energized or use a relay tester and replace any failed relays. Acquire the electrical wiring diagram and locate ground points and common ground junctions; the harness junctions in these vehicle were known to corrode and cause a lot of electrical problems.

The junctions sometimes look like a connector with a lot of white/ white with a black stripe, or black wires and bolts down to ground the entire unit. If one or more of these are corroded, replace as necessary and repair any broken terminals. For further help, YourMechanic has several available technicians that can assist you with an electrical problems inspection and can provide an estimate and direction for repair.

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