I did jumper the pressure switch plug to simulate a good pressure switch with the clutch relay installed no help. The only way to make the clutch engage is jumper the clutch relay itself.

Unless someone else has any ideas after all I have checked with everyone's help, it does appear the ECM/PCM is bad. Any idea what is a reasonable cost to expect from a Honda dealer?

Many thanks to all. I learned a lot.

 

Hang on, I'm not willing to give up yet. If you are willing to do a few more things?

I'm attaching a pic. Two inputs to the relay, key on, should be hot. When the ac is turned on, another will ground, closing the relay and sending power. Test the inputs, test the relay.

 

You can find your ECM on ebay or car-part.com. You need to get the part number from your computer and match the part number to insure no problems. I saw several w/ prices ranging from $50-$100.

good luck

 

I will check for the voltages and ground at pin 3 later today.

Does the ECM have to be programmed for my specific car? Why do the diagrams always refer to it as ECM/PCM? Looking under the dash, it is well confusing and a little intimidating. Hate to make things worse.

Thanks again.

 

Clutch relay voltages are good at pins 1 and 4. Still no ground on Pin 3 from the ECM. Both radiator fans and the inside fan come on with A/C on.

A/C works fine if apply 12v to Pin 2; Compressor clutch then enagages.

At this point, any guidance on ECM replacement would be much appreciated.

 

Well, you are going to need to have the new pcm programed to your keys. Other than that, pretty much plug and play.

 

Can only a Honda dealer program the new PCM to my keys?

 

Unless you have a locksmith with the proper tools, which will be hard to find.

Or you're lucky and can get the "key" that is programed to the new ecu. Yes the "new" key won't work your locks but you can drive the car and make sure this solves the issue.

 

ECM replaced at the local dealer. $800. So far so good.