Skip the auto shop - Our mechanics make house calls

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

asked by on

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.

Was this answer helpful?

Need advice from certified mechanic? Get help now!

Over 1000 mechanics are ready to answer your question.
The statements expressed above are only for informational purposes and should be independently verified. Please see our terms of service for more details

Ask a Mechanic
(100% Free)

Have a car question? Get free advice from our top-rated mechanics.

Ask A Mechanic
Over 10,000 questions answered!

Get an instant quote for your car

Our certified mechanics come to you ・Backed by 12-month, 12,000-mile guarantee・Fair and transparent pricing

Get a quote

What others are asking

Q: Stop at stop sign, give it the gas, it want go, let up, push down agin it goes,the engine does not die.!!!!

What you are describing sounds like a dirty or failing idle air control valve. The idle air control valve monitors the air intake as it is mixed with fuel prior to being injected into the engine at low speeds and...

Q: So I did an oil change about three weeks ago today I noticed the temperature gage moving up going back down went up again but not

Claimed by John Hege

Q: Transmission slipping at third gear

There are a couple of possible issues. Looking at Ford's technical service bulletins, possible issues range from water intrusion in a sensor to a possible warped separator plate between the valve body and transmission case to possible internal wear in...

Related articles

P0052 OBD-II Trouble Code: HO2S Heater Control Circuit High (Bank 2 Sensor 1)
P0052 code definition HO2S Heater Control Circuit High (Bank 2 Sensor 1) What the...
P0240 OBD-II Trouble Code: Turbocharger Boost Sensor B Circuit Range/Performance
P0240 code definition Turbocharger Boost Sensor B Circuit Range/Performance What the P0240 code means P0240 is an OBD-II generic code triggered when the Engine Control Module (ECM) detects the intake boost...
P2428 OBD-II Trouble Code: Exhaust Gas Temperature Too High Bank 1
P2428 code definition A P2428 trouble code signifies that the PCM has detected a problem in the exhaust gas temperature sensor circuit in bank 1, which subsequently contains the number one...