My speed control broke & Ford can't fix it! (Way off topic)

Tom Wells · #1 (**permalink**) 03-18-2011, 06:18 PM

I have a 2006 E-150 van with the 5.4. My speed control failed.

Not all at once, mind you, but first the light on the instrument panel wouldn't illuminate - the speed control continued to work fine. It just didn't tell you it was on.

Then later - maybe two or three months later - it started disengaging unbidden. Then shortly it wouldn't work at all.

Being a good (really good!) parts thrower I replaced all the switches I could. Steering wheel. Brake master cylinder. Speed sensor in the differential. No change to any of the symptoms.

So I took it to the Ford place. They have a sooper-dooper diagnostic computer that probably costs more than the car. Just for the speed control!

They replaced the master cylinder switch I already replaced. No luck.

They replaced the PCM. No luck.

They replaced the clock spring. No luck.

They kept it four days; they gave me a loaner car. Today they gave it back still inoperative.

Anyone got any ideas?

Tom

Jerry Clayton · #2 (**permalink**) 03-18-2011, 06:50 PM

Well I have a 1999 F350 crew cab diesel powered pick up----my speedo stopped working 4 or 5 years ago at 230,000----of course no crz control or anti skid---

I replaced the rear ring gear sensor and now speedo , crz ,anti skid ,everything works---

Except---below 8 mph my dome lites come on and then off above 8 mph.

Barnsnake · #3 (**permalink**) 03-18-2011, 07:04 PM

I had a similar problem on a 2002 Explorer. Sometimes the cruise would not set. Light worked, just would never set. Next time it was driven it would work fine. Couldn't find the problem. After several months the HVAC started losing its settings after each shut off. I found an internet post that claimed a bad battery would cause that.
Out of desperation I replaced the battery that seemed to be working fine (cranked every time). The Cruise and the HVAC have been flawless since.

Racer_X · #4 (**permalink**) 03-18-2011, 07:20 PM

I agree with Barnsnake. try the battery. overall running voltage could be too low. also could be alternator with bad diode throwing a/c voltage into the circuit. is the any speed sensor at all on the trans besides the speed sensor on the differential?
Bad or leaking vacuum source to the cruise slave vacuum motor?