I reconnected everything.
Ignition in run position.
Turned on the CC.
No power to servo.

I traced the yellow wire with the red tracer to the PCM, cut and tested continuity...The wire has no breaks.

I'm stumped.

 

Did the cruise control light come on? I'd start the truck. The PCM "knows" whether the truck is running or not.

I think your options are PCM or servo. I still think it's the servo. You can get them out of the boneyard, usually pretty cheap, but even new I don't think they're that expensive.

Or, a dealer can hook up their DRB and actuate the entire system.

 

Thanks for your help...I did 3 new tests.

All test performed 3 different ways:
With no key in ignition.
Key in run position.
Truck running.

Test 1
Truck in normal condition with all wires and switches connected.
CC button off = No power to the servo.
CC button on = No power to the servo.

Test 2
Brake plug 1 & 3 jumped = Power to the servo.
Brake pin in or out = Power to the servo.
It didn't matter if the key was in or not.

Test 3
Brake plug 1 & 4 jumped = Power to the servo with no brake pedal pressed.
Brake plug 1 & 4 jumped = No power to the servo with brake pedal pressed.
It didn't matter if the key was in or not.

Conclusion 1
Test 3 is how the CC should function without a jumper.
Why does the jumper give the correct results?

Conclusion 2
The non functioning CC has kicked my ***.
Truck wins...Man fails.

 

Test 3 is only showing the results because you are bypassing the PCM power supply. That's what is supposed to feed the cruise control, not the +12v you're tying in to.

It can be a PCM problem. It can also be the servo. I'd favor the servo as something damaged it.

Can you hook up a meter and drive the truck to check for power to the servo while above 30 mph? So that the PCM is supplying power.

Otherwise, if you don't want to just throw parts at it, a dealer can actuate the entire system with a DRB and troubleshoot it. It will test all the switches, everything.

Really it isn't a complicated system. A few switches, the PCM, and a servo. That's it.

I don't think it is the PCM though. If you see the "cruise" light then you are getting a signal from the PCM over the PCI bus.

 

Thank you so much for your continued help!
Yes, am I looking for 12v through my meter?

I suck at measuring voltage but I'm going to guess that I:
Connect to #3-V30 20DB/RD BRAKE LAMP SWITCH OUTPUT and the other end to a good ground?

1-V36 18TN/RD SPEED CONTROL VACUUM SOLENOID CONTROL
2-V35 18LG/RD SPEED CONTROL VENT SOLENOID CONTROL
3-V30 20DB/RD BRAKE LAMP SWITCH OUTPUT
4-Z1 18BK GROUND

 

I'd check it at pin #3 on the brake switch. Why run a wire outside? You know you have continuity.

Yes, to a good ground.

If you want to get fancy, can you hook up to pin #4 as well? Then you can test both sides of the brake switch. If you get power on 4 and not 3, the PCM isn't outputting power. If you get it on both, you know it's not the PCM.

I like chasing wires. Just give me a schematic!

 

I'll go drive it right now...Meanwhile check this out.

Found this auto start module stuffed up under the dash.


I removed it one wire at a time and inspected all the wires and one black with light blue tracer wire was nicked. It goes up to the steering wheels "set" button. I cut out the nick and re-soldered it together but the CC still isn't working.

I wonder if the "set" function of the switch is bad? Chiltons wiring diagram shows that blk/ltblu wire running through a box that is not labeled. Then the wire runs to the sensor grd at the PCM.

 

Okay...I think you're on to something.

I hooked up both pins as suggested:
First pin #3...While driving there was no voltage through the meter. I activated the cruise "on" switch and the light came on the dash and voltage registered at 17 (Harbor Freight meter, it reads a 9v battery at 12 something). When I applied the brakes the voltage dropped to 0.0.

Now for pin #4...While driving there was the same voltage as pin #3. When I applied the brakes the voltage did not drop.

 

The brake switch is working correctly as is the PCM feed to the servo.

The PCM is supplying power when you activate the system.

It should read "0" when you hit the brakes, you've opened the circuit. It's normally closed with the pedal "up."

What do you mean those wires go to the "set" button? All the cruise control functions are multiplexed on 2 wires. If you disconnect the harness at the steering wheel so the switches aren't powered, you'll notice a specific ohms reading when nothing is depressed. As you work each switch it will change value. NOTE: it won't show open - ever. This is how it is designed, so as to provide a check.

If you follow the wires to the PCM, you can check the entire run. I don't have the pinouts as they changed PCM's in '02. You should have 4 connectors, earlier has 3.

 

Good!

Right under the steering column there is the blk/ltblu that was nicked. According to my Chilton wiring diagram that wire is connected to the "set" button on the steering wheel.