Has anyone had the cold engine, wait to start, indicator light, start blinking and chiming, while driving down the highway? The light is coming on while I am at driving at posted speed limit, and remaining in a blinking state, for 45 to 75 seconds. Comes on and goes back off at random times. Should I be concerned about this happening?

 

OPERATION
The wait-to-start indicator gives an indication to the vehicle operator when the air temperature within the diesel
engine intake manifold is too cool for efficient and reliable engine starting, and that the intake air heater grids are
energized in their pre-heat operating mode. This indicator is controlled by a transistor on the instrument cluster
circuit board based upon cluster programming and electronic messages received by the cluster from the Engine
Control Module (ECM) over the Programmable Communications Interface (PCI) data bus.
The wait-to-start indicator Light Emitting Diode (LED) is completely controlled by the instrument cluster logic circuit,
and that logic will only allow this indicator to operate when the instrument cluster receives a battery current input on
the fused ignition switch output (run-start) circuit. Therefore, the LED will always be off when the ignition switch is
in any position except On or Start. The LED only illuminates when it is provided a path to ground by the instrument
cluster transistor. The instrument cluster will turn on the wait-to-start indicator for the following reasons:
² Wait-To-Start Lamp-On Message - Each time the cluster receives a wait-to-start lamp-on message from the
ECM indicating that the air temperature within the intake manifold is too cool for efficient and reliable engine
starting, the wait-to-start indicator will be illuminated. The indicator remains illuminated until the cluster receives
a wait-to-start lamp-off message, until the ECM detects that the engine is running or until the ignition switch is
turned to the Off position, whichever occurs first.
² Actuator Test - Each time the cluster is put through the actuator test, the wait-to-start indicator will be turned
on, then off again during the bulb check portion of the test to confirm the functionality of the LED and the
cluster control circuitry.
The ECM continually monitors the engine intake air temperature sensor to determine when the intake air heater
grids should be energized in their pre-heat operating mode. The ECM then sends the proper wait-to-start lamp-on
and lamp-off messages to the instrument cluster. For further diagnosis of the wait-to-start indicator or the instrument
cluster circuitry that controls the indicator, (Refer to 8 - ELECTRICAL/INSTRUMENT CLUSTER - DIAGNOSIS AND
TESTING).
For proper diagnosis of the engine intake air temperature sensor, the intake air heater grid control circuits, the ECM,
the PCI data bus, or the electronic message inputs to the instrument cluster that control the wait-to-start indicator,
a diagnostic scan tool is required. Refer to the appropriate diagnostic information


From a 2005 FSM, should essentially be the same except you have canbus, 2005 being PCM . I guess the very first place I'd start looking is IAT sensor, since it sets up the initial call for the grid heater on/off, and yes---you should be concerned.

 

Thanks Gone Fishin for the reply.
It has only done this on 4 different long drives, 150+ miles, and it is an intermittent happening thing. No rhyme or reason just out of the blue. It will flash maybe 10 times and quit. Then may or may not happen again. I will keep it in check and have it looked at if it happens more frequently.

 

I'm guessing a loose wire possibly, might pull the connector and make sure its clean and tight.

 

Thanks again, I will try that. Can you also tell me why I cannot stop, cold air from A.C., blowing out floor registers, when on the recirculate setting.? I think it is blending door but not sure which one and how to access it.