Hi,

I recently changed out the Engine Harness, now I have a car that starts and idles high. I have isolated it to the IAC not properly actuating. It could be gunked up or there could be some other problem.

I was going to replace the Ignition Harness, and change the ECU and ICU if I can find one. However some posts make vague references to unhooking the ICU as being very bad and wrecking the ECU, although seems people say ECU when they mean ICU sometimes.

If the car is off and the battery is unhooked, I would think it should be fine right??

So I am wondering what is the potential danger of changing the Ignition Harness. Is it just that the plastic connector into the ICU will get slightly damaged and not stay in as well, or is it more concerning like fried computer. I can unhook the battery and swap the Ignition Harness with the ECU unhooked. In fact since I already changed the Engine Harness, and it connects to the Ignition Harness, Did that have the impact on my ECU as unhooking the ICU.

Man, I am too scared to proceed...

The Bentley says not to use 12v bulbs to test circuits as they might draw too much. I don't understand electricity too much. But in this IAC case, can I just get three bulbs and put one in line of each pin on the IAC connector, and connect the other ends of the three bulbs to the correct pins of the IAC. That would allow me to see them flash as the IAC is being actuated right??, or would that be too much for the circuit.

Thanks!