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Daniel, Ford Technician
Category: Ford
Satisfied Customers: 5064
Experience:  Ford Technician
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1995 F150 speedometer problems. I just purchased this truck

Customer Question

1995 F150 speedometer problems. I just purchased this truck about 2 weeks ago.The speedometer was bouncing around and was not accurate. Then about a week after i bought it . it blowed a break line. It seems ever since that happened my speedometer doesnt work at all nor does the odometer. I fixed the brake line i have a ABS light on and my speedometer doesn nothing. The transmission seems to shift ok.I have replaced the speed sensor on the differential housing . I replaced the ECU. i replaced the instrument cluster. i replaced the input speed sensor on the transmission. I took the rear end housing off to make sure the gear was in good shape and no problem there either. I traced the wires from the rear end speed sensor all the way up to the fire wall and under the dash . And no breaks or corrosion at all. Please help.
Submitted: 6 years ago.
Category: Ford
Expert:  Daniel replied 6 years ago.

Programmable Speedometer/Odometer Module (PSOM)

The Programmable Speedometer/Odometer Module includes the Speedometer, the Odometer, and the Trip Odometer, all of which are electronically controlled by a programmable integrated microprocessor. The microprocessor receives a speed signal input from the Differential Speed Sensor (DSS), and uses a programmed conversion constant to convert the signal to the standard 8000 pulses per mile speed signal output. The Programmable Speedometer/Odometer Module is serviceable only as a unit.

The electric analog speedometer receives it's input from the anti-lock brake sensor. The liquid crystal display (LCD) odometer is a combination trip odometer and total odometer. The total odometer is normally displayed. To See the trip odometer, press and release the SELECT button on the upper right side of the speedometer. To zero out the trip odometer, press and release the RESET button on the upper left side of the speedometer while the trip odometer is displayed. If the trip odometer is displayed, press and release the SELECT button to return the display to the total odometer value. The speedometer, containing the trip odometer and total mileage odometer, is serviceable only as a unit.

The speedometer is also used to provide Speed signal for correct operation of the vehicle's EEC module and speed control (if so equipped). Because of this, it is VERY IMPORTANT to change the speedometer's internal conversion constant if the size of tires on the vehicle is changed. Changing the conversion constant to the proper value when the tires are changed will also make sure that the speedometer retains the original factory-set accuracy.



this is the pdf for tesing a remember it has to be tested as a unit.

Customer: replied 6 years ago.
You are saying the speedometer and odometer module is part of the Instrument cluster. IF so i have already replaced the whole cluster. and still nothing.
Expert:  Daniel replied 6 years ago. sorry here is the pdf for testing
Customer: replied 6 years ago.
The diagram you sent me seems to be for a truck with a cable driven speedometer. This is electrical speedometer. with no cable. It is also aXXXXXautomatic. If that changes anything
Expert:  Daniel replied 6 years ago.
I am going to request this testing info for you and it will be morning til I get it. I checked a 1996 also and its sh owing a cable. make sure the wires are not broken inside the insulation like i just found on my van. not a clue except it bends like an elbow with out the insulation messed up at all. see you in the morning.
Customer: replied 6 years ago.
ok thanks
Expert:  Daniel replied 6 years ago.
ok see ya soon
Expert:  Daniel replied 6 years ago.

I had to do a bit extra to get this.



Sorry so late.