2nd Gen Non-Engine/Transmission Help! Cruise is dead and i cant fix it!

[biggy238]

I'm sure you guys are onto something, but you should check out what the throttle position sensor is doing, that is, if all else checks out. I know my truck is an older model, but the light won't come on unless the speed and tps are up to par. Just a thought.

 

[CCutshaw]

Brakelight switch pin 3 yellow/red is the speed control power supply, from the powertrain control module. Pin 4 from the brakelight switch darkblue/red connects pin 3 of the speed control servo. Pin 3 to pin 4 of the brakelight switch is normally closed. Not good if you don't have 12 volts from the PCM. The PCM controls the charging system, speed control, transmission, and AC. Its inputs come from the engine control module. Check the clockspring wires.



From clockspring # one pin 1 red/light green to pin 32 of the PCM, pin 2 black/violet to ground, pin 3 black/light blue to pin 4 PCM



from clockspring # two pin A dark green/red to the left speed control switch/right speed control switch pin 2 on both switches. pin B white to pin 1 left speed control switch/right speed control switch.



Hope it is one of the 22 gauge wires in the steering wheel.



Correction when you check for 12 volts on pin 3 yellow/red from the PCM make sure the engine is running.



Calvin

 

[SMalafy]

I had problems with my cruise and found that the plug going in to the brake light switch was loose because I accidentally broke the clip off of the brake light plug. Because of the loose plug Iwas not getting any current to the servo and I hooked up a jumper from the PCM to the servo. The cruise still worked with the jumper and would shut down when I hit the brakes. Steve

 

[JRichard]

Pcm?

When you guys say PCM, do you mean the one on the side of the engine, or something elsewhere? Just wanna make sure im testin the right things heh



Jake

 

[JRichard]

Here we go

Okay, i have some results for you ... .



Red/Light Green from clock spring to PIN 32 of PCM has continuity

Black/Violet from clock spring to ground has no continuity

Black/Light Blue from clock spring to pin 4 of PCM has no continuity



Looks to me like a broken wire in the column or elsewhere, anyone else concur?



Also another question, should the yellow/red at the brake switch have power with the truck running ONLY after youve pressed the cruise switch? In any case mine never has any power, it does however have continuity to the PCM...



Jake

 

[JRichard]

Woooooo, i have a cruise light for the first time, the black/light blue wire was broken somewhere between the clockspring and the bulkhead connector, im gonna hook everything up and go for a drive.....



Jake

 

[CCutshaw]

Like DCTECH said you need to replace or repair the wire harness from the clocksprings to the PCM. Yes, the PCM is mounted in the right rear side of the engine compartment. Yes the Yellow/Red to the brakeswitch will only have power with the truck running after you press the cruse on switch.

Calvin

 

[JRichard]

Fixed

Thanks for all of the information guys, i repaired the black/light blue wire from the clockspring. Thanks to this information i got it fixed and my cruise works for the first time ever!!!!



Can't thank you enough, i have an upcoming trip to Chicago this week so we'll get to try it out.



:-laf



Jake

 

[CCutshaw]

Great job Jake.

Calvin

 

[fest3er]

Hmmm. I have some continuity checking to do. My CC just quit; instrument cluster light never comes on. Sounds like I might have a busticated wire under the dash.

 

[wtrenholm]

Just fixed the cruise on the wife's 98 gasser last week and the black/blue wire (which is the ground for the switch) was broken about two inches from the clock spring connector.



Also, when I put the scan tool on the truck the equipment screen displayed "Cruise - not equipped"; which was a result of the PCM not seeing the proper voltage drop on the cruise switch input.



HTH,

Wayne

 

[fest3er]

Just fixed the cruise on the wife's 98 gasser last week and the black/blue wire (which is the ground for the switch) was broken about two inches from the clock spring connector.



Also, when I put the scan tool on the truck the equipment screen displayed "Cruise - not equipped"; which was a result of the PCM not seeing the proper voltage drop on the cruise switch input.



HTH,

Wayne

Scan tool showed no codes on mine. And I did take the switches out; the resistance was within reasonable tolerances.



Some years back, the shop disconnected the A/C from the PCM after the A/C quit, since there's really no reason for the PCM to control the A/C on these diesels. I have a niggling fear that more of the PCM is gone now. But I have to go through the full physical diagnosis first. When it's a little cooler out.



N

 

[HughO]

That's the differential speed sensor I think. I have 2 12 valvers, a 94 and a 97. On my 94 I noticed the cable was shredded near the differential end . The speedometer worked, the cruise didn't. I plugged a new cable into the dif and the transmission went crazy and would only shift as far as 3rd. I disconnected it and it shifted fine. I ordered a new sensor and plugged it into the dif and reconnected the cable and it worked perfect. But no lights on the cruise on the 94. I had no cruise on the 97 and decided to take it to the local whiz kids and they condfidently promised me a new ECM would fix it which is what I thought and now some $600 later I have a new ecm and a hole in my checking acct but no CC. The cruise turns on but wont actuate the cruise. A scan turned up no error codes. Is there a comprehensive analyis in old discussion forums where one of the TDR geniuses did a summary and troubleshooting flowchart? I found the service manual problematic... I have to go out and plow with 94 right now. . 12" of new white stuff. . fortunately I plow slow enough I don't need cruise control!!. .