Before I start... Yes, I have read a handful of threads regarding this.

2004 F-350 6.0 4X4 Manual transmission.

When I drive on the freeway I can turn on the cruise system w/ the On switch. When I then use the Set button the green dash light comes on but immediately goes off when I release the button. Hold the button, the green light flashes until the button is released.

If I push in the clutch peddle while coasting down a hill and attempt to turn on the CC the light does not come on. Similarly with the brake peddle depressed.

Periodically the ABS light comes on and I can tell by the brake peddle feel there is an issue with the ABS.

Additionally, the speedo is not accurate. I have an aftermarket GPS. When driving with traffic in a 65 I am reading about 55. My GPS confirms the speed of 65. The speedo flutters with about a 5 MPH span.

Yes, I have tried the Cruise Control Self diagnosis. It does not work on my truck. Key on w/Off button depressed and nothing.

I have checked for codes w/ Auto Enginuity. C1229 & C1184 both come up.

I have replaced the Vehicle Speed Sensor at the top/front of the rear differential.

I have replaced the Cruise Control Cut out Switch on the master brake cylinder.

Both parts are from Ford parts department.

So... What now?

 

Try replacing the cruise control cutout switch that is installed on the master cylinder. I had issues with my CC and my abs was acting funny and I changed it and everything works great now.

 

It's in the shop. Apparently a screw inside the rear end fell out and the ABS ring in the differential is damaged. Perhaps, also, other parts.

The cruise started working as it should when the ABS light came on solid rather than now and then.