Cruise Control Wiring Incorrect

[BigRedMonster]

Hey guys,

Another issue with the truck is the cruise control. Ive tested all the wiring according to thr wiring manual and brake switch however the wiring from the output speed sensor is not correct according to the wiring manual.

The 2 wires from the output speed sensor on the rear diff are "supposed to" connect directly to the PCM on Connector 2 if i remember correct.

They dont they are actually both a different colour and connect to a connector under drivers wheel arch. At the PCM pins where they are supposed to go there is wires that are correct according to the diagram but between the unknown connector in the wheel arch and the PCM i have no idea where the wires go. Also i cannot get any continuity between them. Only continuity from speed sensor to the first connector not shown on the diagrams.

Cheers

 

[cerberusiam]

If it is a 3rd gen the rear diff sensor connects to the ABS module first and the signal is changed from analog to digital and put on the data bus. If you have continuity to the connector in the firewall that is all you can trace. If it is an 03-04 check vacuum lines if you have the CC module and cable.

 

[TWebster]

I was always under the impression the cruise control signal came off one of the unit bearing sensors, maybe I'm mistaken.

After I posted the above, I looked the FSM, and there is mentioned a speed comparison between the front and rear wheels as to maintaining the cruise engage command. Check the unit bearing sensor wires and make sure neither are cut or broken

 

[cerberusiam]

Wheel speed is read form the rear diff sensor, it is dual function sensor. The ABS module looks at the front wheel sensors but wheel speed is pulled form rear diff and put on the bus by the ABS module. Need to know what truck your are working on as it can make a difference.

 

[TWebster]

Wheel speed is read form the rear diff sensor, it is dual function sensor. The ABS module looks at the front wheel sensors but wheel speed is pulled form rear diff and put on the bus by the ABS module. Need to know what truck your are working on as it can make a difference.

Ahhhhh, I stand corrected----Thanks!!!

 

[BigRedMonster]

Ahhhhh, I stand corrected----Thanks!!!

Thanks for the replies guys. Its a 3rd Gen 2003.5 2500. I swapped out the cruise servo for an old one from the junk yard and its all working again.
However the concern remains that the wiring diagrams are incorrect as far as i can tell. I have emailed Chrysler, be interesting to see their reply.

 

[cerberusiam]

You have to have the correct FSM for the correct year or it won't match. ATSG manuals do not take into accont the differences between years or even in years.

 

[BigRedMonster]

Ah okay i thought i had the right manual.
I spoke to Chrysler but they said they didnt have access to the manuals...