2002 Park Ave Ultra 125K

About two months ago I had transmission work - pressure control selinoid and valve-body assembly done followed a week later with new axle and control arm (bushing went). All work was done at my local Buick dealership by the tech who has worked on my car since it was new. He is a GM tech with 30 years experience. With things happening in three'* I thought that would be it for a while. Wrong. After the control arm was fixed, I noticed that my cruise control would not engage at all. The next day it engaged but only after I stepped on the brake each time first and then pressed the resume would it work. Third day I noticed the green cruise control light was going off and on a couple of time intermittently, but the cruise was working. Brought it in and Tim (GM Tech) scanned and found no codes and check with tech II in diagnostic mode for cruise control testing. He found nothing that indicated the problem. He adjusted the switches on brake peddle (all brake lights are working). I drove off to test. The cruise control worked fine except the green 'cruise' light in the cluster would not illuminate (the bulb is working at startup bulb check). The cruise control has worked every time since then without fail, engages immediately as it should and excellerates when using the RA on the control. Stops as soon as you hit the brake and always works again when engaged, but still, no light. We tried a new cruise control module and same results. Everything working except the cluster light. His thought is the PCM is causing the problem. Can anyone shed some light before I invest in a PCM that once programed, I'm stuck with (unlike the cruise module that I was able to return).

Any help would be much appreciated.

I have a 97 PA and I am no expert on cruise control however when I first got the PA a similar situation arised with the cruise on hwy.
The one thing I can tell you is that the PA does not like low voltage situation below 12.5 volts as strange things start to go awonk and make u go hmmmmm....what'* up..??
So with that being said, have your battery load tested. And check the voltage output while driving with a load on....Like...fan on high, lights on rear window defogger and watch the voltages...with a VOM from inside the car while running on hwy and stopped in city traffic. I had to replace the Alternator & went with an odyssey battery for the PA. Sometimes I think the PA is very slow to sense the need for higher voltages and some sort of sensing volt mod needs to be added somehow still.

Just to be thorough, I did disconnect/reconnect the battery as a possibility and that did not help. Battery is 6 months old and voltage is 12.8 to 13.1V with a full load and 13.2 to 13.4V with a normal load. I agree that could cause problems but that is not the case here, I don't believe.

When u disconnect battery it clears codes & some memories etc
You wont really know how volts are doing until you load the system by turning it all on/ driving the car is a must & reading from inside the car.
Here is what I use..the paperclip test LOL...and flashlight accessory (unreduced) 12 volt
plugged into the cig lighter in pk ave.

Worth a try to see how the Pk Ave is really doing.

Thank you for the reply. We checked for codes before I disconnected the battery. I have a voltage display on the Driver Information Center inside the car that is fairly accurate. I did use a full load as you described and my results were the battery/alternator are functioning properly. The cruise control is working fine, without fail for the past three weeks, it'* just the light that is not illuminating.
Nothing else going on electrically.

Your mechanic might be right about the PCM or it could be the insterment panel not recognizing the comand to turn on the cruse light. I would have your gm tech hook up the tech II again and comand the light on. If the IP turns on the light then the PCM isn't sending the comand to turn it on or there is a problem somewhere in the data stream.

Thank you for the reply. If it is the data stream, what would be a solution to fix that? Sounds like it means replacing the PCM, correct?

I have now replaced the cruise control module and the ECM and still the no green cruise light on the cluster when it'* engaged. Cruise works fine and the light DOES illuminate when key it turned for bulb check, no codes either. My next step is replacing the two switches on the brake pedal. *All* rear brake lights are working fine. Could this be the multi-function switch or even the harness that plugs into the cruise control module? Is there a specific wire in either the wiring harness that plugs cruise module or multi function ( I don't have a diagram) that specifically turn the light on when cruise is engaged? This is driving me crazy. Any help is appreciated!

I think that light would fall under the BCM category.

What does that stand for. Body control module? Where is that located?