[CobbAndCobb]

My 99 F550 Ford 7.3L diesel runs great. The transmission sounds like it shifts just fine. However, while driving the speedometer and odometer will randomly stop working, and the overdrive button will begin to flash. I've replaced the VSS, and it continues to have the same problem. If I am at a stop light, put the truck in Park, then back to Drive, the speedometer/odometer begin working again and the overdrive flashing stops after a minute. No fuses are bad. And no, the ABS light is never illuminated.

I don't know if it is related or not, but the reverse lights AND trailer hook up connector closest to the reverse lights do not work...again, no bad fuses.

I've seen some folks mention having the transmission codes read because of the flashing ODS light, but the light is not always on.

What should I do?

 

[StrokinAlaska]

Same boat, minus the rear lights. My front left blinker has no signal to it anymore though. My speedo and odo still work, but o/d just flashes

 

[CobbAndCobb]

I should also mention that the speedo/odometer always work when I first start driving. It will stop working (randomly) when I've made a complete stop, and then when I take off, sometimes it quits working.

 

[CobbAndCobb]

I pulled three DTC codes: P1211, P0603 and P0500. Can anyone please help?

 

[CobbAndCobb]

Come on, boys! 51 views but no response yet? I'm a young 88lb lady here in need of help! I literally know NOTHING about this vehicle, just got it a few months ago out of need (previous vehicle a Camry!!!) and I DO NOT want to get taken at a mechanic's shop. I am going to clear the codes to see what happens, but what should I consider as a problem since the VSS is not fixing my issue?