Hi, I'm messing around with a 1997 3500 CTD, the wait to start light on the dash is trying to tell me something by throwing a "code"? It flashes at a would be code rate and stays cycling at all temps. In addition, I have one heater relay that is energizing at a very fast and erratic rate? Is the ECM trying to tell me something? Thanks for what input you may give in advance, Artie

 

The most probable cause is that you are not getting a good signal from your air intake sensor. Try unplugging the connector that is about 3" from the actual sensor and cleaning it up and putting it back together. It tends to get corroded and cause this problem.