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Dr.Automotive
Dr.Automotive, Auto Mechanic
Category: Chevy
Satisfied Customers: 3803
Experience:  Automotive Degree Dealer Experienced
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2007 Chevy: Silverado..Cruise Control..the brake switch module..PCM

Resolved Question:

2007 Chevy 2500 HD Diesel Silverado Classic Cruise Control works intermittently. Dealer has replaced the brake switch module twice and PCM once. Still will work sometimes then quit or will not engage. Thoughts before I take it in again.
Submitted: 5 years ago.
Category: Chevy
Expert:  Dr.Automotive replied 5 years ago.

snapontech :

Welcome to Justanswer, My name isXXXXX am here to help.

snapontech :

Hello

Customer:

Hi Danny. Cruise control is driving both me and the dealer crazy. As stated it works sometimes, sometimes will not engage and sometimes will engage and then quit. Dealer has replace the brake switch twice and the PCM the last time in. the error code keeps coming up brake switch which seems unlikely every time.

snapontech :

P0575?

snapontech :

or P0571

Customer:

I do not know what the specific code is displayed. All I know is the dealer says is the brake switch code every time.

snapontech :

well there are two of those which can be different if its P0571 which is brake switch malfunction

snapontech :

Then it has to be within that cirsuit

snapontech :

This runs the tail lamps and the signal to the ECM for cruise

Customer:

OK but I do not get why it works intermittently.

snapontech :

This is because something is shorting intermittently

snapontech :

Could be a brake light that is shorting out

snapontech :

Or a wire to the brake switch itself getting a short

Customer:

Thats what I think as well but how would you trouble shoot the entire circuit.

Customer:

If brake lights work, what then.

snapontech :

You will take a test lamp between the stop lap switch signal circuit and a good ground

snapontech :

then check for short to voltage

Customer:

Going to need a little more info on that as I have not tried yet to test the brake switch.

snapontech :

Full Size Image

Customer:

Are there any relays in the circuit that might be temperature sensitive. Or will self reset with by turning the engine off.

snapontech :

No

Customer:

The dealer told me the transmission is also connected to the circuit. Any possibility that the transmission sensor is the problem.

snapontech :

The problem is most likely the connector to the switch itself

snapontech :

This would normally show a code

snapontech :

And you would have problems shifting

Customer:

OK. I am taking the truck in again tomorrow morning. Should I suggest what you have highlighted. A bad connector seems likely to me as well. anything else to suggest?

snapontech :

This is the only thing it can be at this point. The system is detecting a fault in that circuit itself

snapontech :

Those connectors are know for failure as you can see there is a part number on the image

Customer:

OK. thanks. I will get them to change the connector and check the brake circuit. Let me

snapontech :

If you have found my answer helpful please kindly press the green ACCEPT button in the lower right hand corner. Thanks so much in advance Danny

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