Maybe Cheezit will jump back in and comment.

Are you the first owner? Has it ever worked for you?

If not have someone that has the tools check to see that
the CC is setup in the PCM. If it got replaced and that was
not loaded or not loaded correctly that would cause an issue
and not give any codes.



Sean

6.0L Tech Folder

 

I am not the original owner. But, the cruise control worked fine last year when I went to Canada. It worked fine all the way and back. Normally I don't use it ( just using truck around home), when I was checking the truck out for this years trip is when I noticed the cruise wasn't working.

Is there something else that has to be happen before the system can be turned on? Like I notice the doors lock after I get up to a certain speed or something like that.

How about what ever measures the speed? The speed odometer does work fine, tach works fine

 

Well working in the past kills the possibility of having a
PCM not programed.
The post where I put the PDFs in has one for diag and that is the place to start.



Sean

6.0L Tech Folder

 

I tried those diagnostic sheets you sent but I can't really verify anything with them. For instance the test for the clock spring/ input switches. I am on the pins it's calling for to read resistance when buttons are push but only read open. I have the battery ( driver side) out of the truck just to make room to get at the PCM. But, I'm only reading open no matter what button is pushed. So I thought clock spring bad however, when I took it to a shop they verified all the buttons were working with their scan tool.

Is there something else that has to be done or reconnect the battery for these diagnostic tests to work? Have you ever tried these tests?

 

I just replaced a clock spring this last spring and did
most tests with just a meter. The one you don't use a meter
on it the airbag. If you do and it happens to use to high of
a testing current you get an airbag in the face BANG $500

Not fun.

I'll pull up the diagram for the cruse control for you later.
Might show more than the Diag steps.

I find myself that I tend to work from 3 sets of documents,
Mechanical,Wiring and Diag.

I'll get the needed diagram up later. Have to go deal with a harness
problem while I have light and it warmer than last night.

Nasty cold fog.



Sean

6.0L Tech Folder

 

Here is the wiring diagram that I said I would post tonight.

Here you go.



Sean

6.0L Tech Folder

 

Just starting looking at this again....went to the back burner. One thing I noticed is my door locks seem to lock at random times and speeds. The door locks must be operating off a vehicle speed sensor and im sure the cruise control has to operate off one too. Could they be reading off the same one? If so what sensor/sensors does the cruise control read from?

 

The auto lock would act when the speed set speed is reached.
The VSM should have a feed for the VSS but I don't see one in
the diagrams I have. The one way they are connected that I do
see is the CAN BUS and that is all that is needed to command
the lock action.
Do the locks only lock once or do they flicker somewhat like with a short?

I wished I was able to put my hands on the truck so I might find the answer.

I need to put some thinking into this.


Sean <BR>

6.0L Tech Folder