The 2003 F150 Super Cab speedo pops up to about 35 mph when I start the vehicle. Will sit around there and 45 mph - so I judge speed by the Tachometer after doing some checking with Highway Patrol and a radar gun.

Odd thing is that if I get going around 80 or higher it drops to zero - until I slow down a bit then goes back to the 40 or so range again.

Anything I can do to get it working? A cable to replace or contacts to clean or some such? Preferrably not something that costs an arm and a leg to do.

 

Any OBD2 trouble codes? That's an electronic speedo, something is wrong with the cluster, wiring, or speed sensor. Does the odometer work correctly?

 

The odometer works OK. But, last week was driving and the odometer started looking like digital stuff on the computer, then off and then back on. Still worked OK and is doing so now.


Is there a Bentley Manual or Shop Manual to get so I can get up to speed on this truck? Bentley Manual is what I have for the VW diesel pickup - an excellent reference for all things on it.

 

http://www.ebay.com/bhp/2003-ford-f150-service-manual

 

Sounds like some wiring is crossed in the harness going into the dash. The jump to 35 on startup sounds like a typical gauge sweep. I couldn't tell you why the jump at 80 and again at 45, though. Your description of the odometer sure does call for some time to pull the cluster out, though. Maybe some loose wiring or a circuit board contact?

 

You can go into test mode on the cluster and do a forced gauge sweep.


Any other symptoms in the truck? Could be a failing battery causing low voltage in the truck