1995 Ford F-150 speedometer

BBOWEN

MEMBER
1995 FORD F-150
5.0L
V8
4WD
AUTOMATIC
157,000 MILES

The speedometer in my 1995 ford f-150 is not working properly. It will work fine until it reaches 35-40 mph, but then starts jumping around. The odometer seems to be working correctly. I have replaced the diff. Sensor, trans. Sensor and speedometer head with no luck. The truck has been sitting idle for about a year. Any help would be appreciated.

3 Replies

HMAC300

MECHANIC
48,601 POSTS

This could be a wiring issue or the item in the picture which is an amplifier for the speed sensor not sure if a scanner will pick that up or not. See picture.

Image (Click to make bigger)

Was this

answer

helpful?

Yes

No

Tuesday, April 6th, 2021 AT 5:35 PM

BBOWEN

MEMBER
2 POSTS

Checked wiring and all seems okay. Any way to check amp? Could a bad ground to dashboard cause this? Thanks.

SPONSORED LINKS

Was this

answer

helpful?

Yes

No

Tuesday, April 6th, 2021 AT 5:35 PM

HMAC300

MECHANIC
48,601 POSTS

I guess the ground could as well as a bad or poor connection maybe at cluster. Never really thought about it. But if the amplifier was not working or had a bad ground it might do it as it would get a ground then send the signal then not. It is almost twenty years old so it could be a bad ground from battery considering the age of it. Or one that is supposed to be there and is not or it can even be dirty battery terminal ends. That is about all I can think of. Check the fusible links in pic they should have power on both sides same as battery and wiggle them around to test as it may have just a few strands attached and not making good contact that may do it as well. Kind of hard to figure out without seeing it.

Image (Click to make bigger)