I have a 98 Dodge Dakota With a 5.9 swap 2 years ago And last week it just died. I change the computer I've checked all the sensors, I unplugged all the sensors and have no communication with Old or new computer with the code scanner. gauges do not work, ads relay clicks on off when I unplug the computer at the harness. Purple and white wire From the TPS, The CPS,Has both positive and negative power going through it only when plugged in to the cpu. No power at coil when cranking. I'm lost, I was leaving work and never made it out of the parking lot.

 

Also something strange happened just now. I left the key on and forgot about it and when I unplugged and replugged the connection toward the front of the computer the engine turned over. Could the key switch have gone wacky. Can it be tested?....and the ac coil engages and the switch is off.

 

If The key is left on in the run position it should not engage the starter. It sounds to like the key it sticking in the start position.