1995 Ford F-150

CMRNLC

MEMBER
1995 FORD F-150
V8
4WD
AUTOMATIC
200,000 MILES

Ok I have a 1993 f150 with a 1995 engine and trans in it. All of a sudden my trucks speedometer reads zero, it shifts at weird times, it slips, the od light blinks, and kicks into gear. I replaced the speed sensor (above the rear axle) and that didnt do anything. What should I do

2 Replies

MERLIN2021

MECHANIC
17,250 POSTS

SPEEDOMETER

Except Explorer & Ranger

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1. Turn ignition on. For all models except Aerostar, go to next step. On Aerostar, If ANTI-LOCK warning light comes on, go to next step. If ANTI-LOCK warning light does not come on, refer to the ANTI-LOCK BRAKE SYSTEM - 4-WHEEL article in BRAKES. 2. On all models, observe odometer. If odometer display is on and digits appear normal, go to next step. If odometer display is not on and/or digits do not appear normal, go to step 6). 3. Observe odometer. If word ERROR appears, replace speedometer. If word ERROR does not appear, go to next step. If the word ERROR 3 appears see RESET CONVERSION CONSTANT. 4. Test drive vehicle. If odometer accumulates mileage, go to step 9). If odometer does not accumulate mileage, go to next step. 5. Test drive vehicle. If indicated speed on speedometer increases with increasing vehicle speed, speedometer is okay. If indicated speed does not increase, go to step 8). 6. Remove, check, and install fuses No. 8 and 17. If fuses are okay, go to next step. Replace fuses and repair shorted wires, if necessary. If speedometer and odometer still do not operate, go to next step. 7. Turn ignition on. Backprobe terminals No. 1 (Light Green/Yellow wire) and No. 3 (Pink/Black or White/Purple wire) of Programmable Speedometer/Odometer Module (PSOM) harness connector, located behind instrument cluster. If battery voltage does not exist, repair appropriate wire from fuse panel. With ignition off, measure resistance between terminal No. 2 (Black/White or Pink/Orange wire) and ground. If resistance is greater than one ohm, repair Black/White or Pink/Orange wire. 8. Set DVOM to measure AC voltage. Backprobe PSOM terminals No. 4 Red/Pink wire) and No. 5 (Light Green/Black wire). Test drive vehicle. If voltage increases smoothly from zero to approximately 3.5 volts as vehicle accelerates to 30 MPH, replace speedometer. If voltage does not increase as specified, repair speed sensor circuit. See appropriate chassis wiring diagram in WIRING DIAGRAMS. 9. Test drive vehicle. If indicated speed on speedometer increases with increasing vehicle speed, speedometer is okay. If operation is not as specified, replace speedometer.
All tires should be the same size, preferably the size marked on the sticker.