Cruise control problem

[BSeyler]

The cruise control on my signature 2000 CTD has been flawless, until recently.
Symptom: The cruise light on the dash will illuminate on startup, along with other normal lights, and shut off after start diagnostics.
When driven, the cruise light on the dash will come on when on/off button is pressed, but seemed to go out if steering wheel was turned. It would not come back on until the next key cycle.
First step: check for DTCs. None found.
From what I understood from my FSM, I decided to replace the clock spring.
Test run: everything appeared good for a couple of miles, then it shut off. I was able to set a couple of times after that. Now, it shuts off as soon as set is pressed.
Next step: check grounds. I could not find a problem there. Everything but cruise works.
Check again for DTCs. None.
Thoughts, anyone?
Thanks!

 

[petersonj]

Check the wiring in the tilt wheel area. There is a cover underneath the steering wheel that is easy to remove. You will see several wires there that get moved back and forth when the tilt wheel is operated. Some of those wires go to the cruise control switches and some go to the clock spring. Check them carefully, the insulation may be intact, but the wire strands can be broken.

I have had three cruise control failures over the life of my truck (375,000 miles). All of the failures were broken wires in that location. I have yet to have a clock spring failure.

- John

 

[BSeyler]

Thank you. I’ll check them in the morning.

 

[SnoKing]

Also I believe that CC vacuum unit and such is under the drivers side battery and is noted to have corrosion issues.

 

[BSeyler]

Also I believe that CC vacuum unit and such is under the drivers side battery and is noted to have corrosion issues.

That is correct. I had that issue on my previous, 1999 CTD. It would always come on, but often times turned into a runaway. This just seems to be an issue with power. I also discovered I have no power to the bulb in the ignition switch bezel. We just got done haying, so I’m cleaning up with the batwing mower this morning. I’m hoping to get back to the truck in a little bit. My wife thinks the aesthetic appeal of the farm is more important than my old pickup…

 

[petersonj]

If I recall correctly, the cruise control on the manual transmission trucks is controlled solely by the ECM. There is no vacuum control unit. @bseler, was your previous truck an automatic?

- John

 

[Ozymandias]

Measure the Ohms of every single button at the steering wheel independently.
That way you that you haven't a problem there, these buttons are known for going bad.

Another option is a bad brake light or clutch switch that signals pedal action where there is non. Sometimes just vibration is enough to close the circuit.

 

[BSeyler]

If I recall correctly, the cruise control on the manual transmission trucks is controlled solely by the ECM. There is no vacuum control unit. @bseler, was your previous truck an automatic?

- John

Previous truck was 5 speed. ST trim level. This one is SLT Laramie. Otherwise, same. On the 99, corrosion in the speed control servo was the problem. I replaced it and everything was fine. I can see the servo under the battery on this pickup. However, these symptoms are different. Just by feel, the wires in the column seem OK. I am going to run it down the highway and wiggle them around a little bit and see what happens. If the problem persists. I think my next step is to test the switches in the steering wheel, as Ozy suggests. My mind keeps leaning toward a bad connection that can’t carry the current when cruise is set….

 

[BigPapa]

AllData makes no mention of a difference between manual and auto on a 2000 model.

SPEED CONTROL SYSTEM
The speed control system is electronically controlled and vacuum operated. Electronic control of the speed control system is integrated into the Powertrain Control Module (PCM). The controls consist of two steering wheel mounted switches.

The speed control can be disengaged manually by:
- Stepping on the brake pedal
- Depressing the OFF switch
- Depressing the CANCEL switch.
- Depressing the clutch pedal (if equipped).

 

[BSeyler]

Okay, I headed down our lane and turned CC on and the dash light illuminated. I wiggled the wires that plug into the clock spring as I went. Light stayed on. I turned onto the highway and it went out - darn it. I pulled over and restarted the pickup and tried it again. Everything worked fine. I accelerated, coasted, turned CC off and on probably a dozen times with no problem. So, I guess I’ll unplug every connection and spray with electric cleaner and see what happens. Thanks for all the advice!

 

[NIsaacs]

Are your batteries good, good connections? Maybe disconnect them for bit. When you reconnect them, maybe rebooting the ECM will help.

Since you indicate, everytime you loose cruise, the light goes out, that would indicate it is in the on/off circuit. If something with the vacuum, brake switch, clutch switch and cancel switch is intermittent, the light should stay on.

 

[BSeyler]

Batteries check out and connections clean. It worked well going to town 8 miles. On the return trip, worked fine until I pushed cancel, then pressed resume, it all quit. I sprayed the plug going into the clock spring with electrical cleaner. I’ll have to try again tomorrow - company arriving…
Still thinking bad connection, wire, etc…
Tomorrow I’ll have a look at switches.

 

[petersonj]

AllData makes no mention of a difference between manual and auto on a 2000 model.

Thanks for that clarification.

- John

 

[SnoKing]

If I recall correctly, the cruise control on the manual transmission trucks is controlled solely by the ECM. There is no vacuum control unit. @bseler, was your previous truck an automatic?

- John

On 2001-2001.5. manuals were ECM, all were ECM in 2002 I believe.

 

[Ozymandias]

On 2001-2001.5. manuals were ECM, all were ECM in 2002 I believe.

And then back to Vacuum for the 3rd Gen?

 

[BSeyler]

I looked and tried to find new CC switches, and it seems like they are like hen’s teeth. The only ones I found were used. So, I took them out and cleaned them up with electrical cleaner. I put everything back together and went for a test drive. Nothing changed. OK, button it all up and call it a winter project.
But, that’s kind of a weak hearted way to end this... I went back out on the highway, and pressed the on button, the dash light came on, and I held the set button for about ten seconds. It worked fine. I did that probably a dozen times. So, I am not sure if that means something weak about the switch, or something on down the line. I will drive it for a few days and see what happens. Thanks for all of the ideas! And, I will report back what happens in the next few days and will continue to try to find new switches.

 

[Ozymandias]

Like said, you can measure the switches resistance.
If there is something just slightly wrong it won't work and go fail safe.

 

[BSeyler]

I went to town this morning and cycled the CC about a dozen times, holding the set button for about ten seconds each time. Everything worked, including cancel, resume, and coast. I shut off and restarted it and cycled a bunch on the way home. Flawless. I think I’ll still try to find some new switches to have on hand. I hate throwing parts at something, but feel I may be glad to have some in case I have more problems, given the scarcity of replacements. I sure like this truck, even though it’s getting long in the tooth!