Speedometer not working and O/D light blinks,
I have a 450 and a 250, 99 and 2000.
On 450 this is an intermiting problem. Stop truck turn ignition off, restart and it all works now.
Just started on my 250 and stopping and turning ignition off cures the problems for a few seconds, after i get moving the speedometer doesnt work and then light starts blinking again O/D light.
Where do i need to start?
Sorry this might sound confusing, i might not have explained it right?
Thanks in advance
Steve

 

It could be the vehicle speed sensor (vss). Its located on the top of the rear differential. Try cleaning the plug first. If it still does it ,you'll probably need to replace the sensor. Use an OEM replacement part. Its not an uncommon failure.

 

I heard a while back that the NAPA replacement part was better that the Ford OEM......I replaced mine with a NAPA over 4 years ago, and so far no problems....

If I hadn't heard about the NAPA unit, I would have surely sought out the Ford OEM.....

 

1. Flashing TCIL

2. Diagnostic Tools Required: OBD-II On-Board Diagnostics, Phase 2 Vehicle Media Communications Unit (Scanner) / Pressure Gauge, Line, and Fitting / DVOM

3. A Flashing TCIL is an indication the Transmissions electronic circuit has identified an anomaly in its operation.

4. It will be necessary to read the Diagnostic Trouble Codes to identify the specific code(s) which have been stored to assist in diagnosing the trouble (P-102 - P1783 Fault Code Identification Chart).

5. Testing:

a. DTC Fault Code Retrieval

b. Circuit Monitoring

c. Circuit Integrity

d. Pump Pressure

w / No Gauges

Trucks with the 4R100 Automatic Transmissions (1999.5 -2003 MY) which present with a "No Accelerator Pedal accompanied by a No Gauge Activity". Circuits: "N250, C212, 20140, 2135, 281a, and 220c" and Fuse #45 in the Under Dash Fuse Panel.

Most Probable Cause: Wire chafing in the steering column coat clutch on/off switch (Overdrive).

Repair: Remove Steering Shaft Decorative Coverings and inspect the wiring for chafing. Covering any exposed wiring with a suitable insulating product to prevent a reoccurrence.

 

I had your same problem years back and replaced the VSS at the diff and it solved my problem ever since.

 

Another vote for the VSS on the rear diff.

 

well i had vss on transmission and on differential replaced and still having the same problem??
Any more ideas?
Thomas White, did i read in your post possible fuse #45 in under dash fuse panel?

 

is the ABS light on? my 02 is doing the same thing. no speedometer, no odometer, no cruise, mushy brake pedal, OD light flashing, ABS light on and no communication through the OBD port with the GEM or ABS modules. . but mine is a bad ABS module or plug going into the module.