Update. While driving home today I was fooling around with the CC and it actually started working! It held pretty well at 65 mph. Then I couldn't get it to work again after kicking it off with the foot brake. I'm leaning towards a problem with the steering wheel switches but it was good to know the system can work!

 

Another update... driving to work last night I played with the system some more. Would not engage. Driving home this AM I took another route that puts me on a road with 65 mph speed limit (last place I got it to work). I hit 60, activated the steering wheel switch and bingo, it grabs hold.

Here's the deal, the CC will not engage below 52 mph. If I get above 52, it will hold and wok fine. If I try and engage it below that speed, it will not activate. With the CC activated and holding, if I bump down the speed with the steering wheel button it will drop offline completely once dipping below 52 mph.

I have another ECU to try and will likely pop that in later today.

 

My diagnosis was correct. It was the CC ECU. Got a used one from the recycler and now it works great. Good luck.

For others reading this, if I was doing this again, this is what I'd do:

1. Test vacuum lines first. Suck on vacuum pump hose end. If throttle actuates and holds vacuum then move on. If not, check hoses, brake switch, and actuator.

2. Test pump and solenoid by applying ground and voltage to pump pins. There's only 3 pins: ground, pump +, and solenoid +.

3. Using ETM and multimeter, test each terminal of CC ECU for correct input. This will narrow it down very quickly. You'll be able to test if ECU has ground, or power, if buttons are working, if ECU is sending voltage to pump, if speed is being transmitted, etc, all in one location.

 

Just to close this out...new (used) ECU from Jumper (thanks!) fixed it finally. I can now cruise along eating a burger, texting and fiddling with the radio in complete bliss... ;-)

 

Ugggg....ECU was the fix. I just installed a recycled vacuum actuator, the PO removed it for some reason. Next for me are the vacuum lines. Hopefully it will work. If not, going to use this thread for trouble shooting.....

Good job guys in figuring it out!

 

Maybe I should finally fix mine...if only there was a road longer than 18 miles without a stop sign to test it on....