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hello, im hoping someone knowledgeable could help me.i have a 94 f250xlt and was towing a trailer when the speedo started going nuts then i lost top gear. i unhitched the trailer and the truck actually drove very well home no problems. thanks in advance for your help
Info from the speedometer is used by the computer to tell the transmission when to shift. The vehicle speed sensor is located in the differential housing of the rear axle. Pull codes to verify problem, and appropriate corrective action.
I am unaware of any connection between trailer lights or brakes and the vehicles speedometer, or computer.
Info from the speedometer is used by the computer to tell the transmission when to shift. The vehicle speed sensor is located in the differential housing of the rear axle. Pull codes to verify problem, and appropriate corrective action.
I am unaware of any connection between trailer lights or brakes and the vehicles speedometer, or computer.
thanks for reply mrollings53, check engine light did not come on.i was driving along when the speedo started bouncing all over the place then i lost forward power as if the trans went into neutral.so i had no third or overdrive but i did have second,pulled over and stopped.had no cell reception so i unhooked the trailer and decided to see how far i could get driving the truck.truck drove perfect.my question was,is the speedo craziness linked with the loss of gears in the trans.?if so why is the truck driving fine now? electrical gremlins or something else?
Yes, there is a connection between the Brake On/Off (BOO) switch and the computer. When the computer senses the brakes have been applied it will unlock the torque converter. The speedo "bouncing" may have been the converter locking and unlocking as commanded by the PCM (computer). The BOO signal comes into the PCM on Pin 2 (Gas engine).
FYI...you can have a stored code or issue that would trigger a code in the KOEO tests with having an active Check Engine Light or blinking TCIL (O/D light on the end of ths shifter).
