I have spent the last week searching here and google and haven't found an answer to my problem. The problem is my cruise control indicator light doesn't come on on the instrument cluster. I have 2007 dakota slt quad 3.7. It does have the ETC so my cruise system is all electronic. I have read the FSM over I dunno how many times. I have checked the voltage at the plug end of the switch and it has 5 volts. I disassembled the switch down to the circuit board and all the metal contacts have 4.53 volts except of course the ground doesn't. I have done the instrument cluster actuator test for the cluster. No cruise indicator lights up. FSM says the LED light is completely controlled by the cluster circuits and programming, and will only light when given a path to ground via the transistor. It further said if any LED indicator or gauge fells to work during the actuator test then the entire cluster panel must be replaced. I was wondering if anyone has come across this, and if there is something cheaper than replacing the entire cluster panel? I just can't believe the LED light being out doesn't allow me to operate the cruise control unless it needs that light to complete the circuit back to the PCM letting it know that it is on.

 

The light won't ever come on if the cruise control does not work. I think you are barking up the wrong tree. Have you checked all your bulbs? Brake lights and 3rd brake light bulbs burned out will kill the cruise.

 

The service manual I'm looking at is for a 2005. Mine is a 2007. I have electronic throttle control with no speed control servo or vacuum resivor and no cruise cable to hook to the throttle. Nothing is wrong with the brake switch all lights are working. From my understanding via the manual the brake switch doesn't control the power input for the switches. It supplies the power to the speed control servo vacuum dump solenoid. Once the pedal is pushed the circuit closes and powers the dump solenoid and stops the cruise control. The switches send their signal straight to the PCM which then signals to the instrument cluster via the CAN Bus to turn on the indicator light. The programming in the cluster circuit allows the transistor to close the ground path for the LED light and it turns on. During the cluster actuator test the cluster uses only it's programming to make sure the cluster is working properly. During the test it doesn't receive signals from anywhere else. During that test my cruise light does not come on so I am assuming the led light is burned out or there is a ground problem. I was wondering if anyone knew a work around for that because I am assuming that led light completes a return circuit back to the pcm allowing you to set the cruise and what not. If I am wrong about this then please correct me.

 

An incorrect signal from the left front or rear wheel speed sensor could cause this.
An incorrect signal from the cam, crank, MAP, APPS, TPS, etc could all cause this. Most of things will set a fault code, but not always.
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There's a good chance that there is just a switch problem, especially if the light will no longer come on. The switches work on a resistive multiplex theory, varying a pullup voltages by putting it through a different resistor for each switch position. If the engine controller is seeing a voltage from the switch that is out of range then it's not going to know what button you have pressed and the cruise won't turn on

 

The switches are on the steering wheel. Replacing a cruise switch involves removing the airbag and then removing the switch from the steering wheel. Total cost to diagnose and then replace a switch would be in the $100-150 range depending on the shop's labor rate.

 

Thanks superdak I could never find out how the pcm interrupts the voltage from the switch. I have had the left side switch off the steering wheel and took it apart. I figured those tiny resistors changed the voltage somehow. I was getting 5 volts from the metal contacts on the switch board. I guess I need to find the return voltage just to be sure. The thing that is throwing me for a loop is the manual says the cluster's circuitry and logic solely control the illumination of the indicators because it doubles as the BCM, and if during the test one does not light then the entire cluster must be replaced. I guess it's confusing me because it says it will light when it receives the path to ground from the transistor. I can't find anywhere saying once the cluster lights cruise indicator it will send a voltage signal back to pcm. I just find it hard to believe that the LED light possibly blown would shut down the cruise system. Unless it needs the light in order to send a signal back to the pcm.