mysterious cruise control

I have already had the cruise control switch replaced a few months ago on my
'07 ION.3 (manual). It is acting up again and works when the heck it feels
like it. I have tried to notice a pattern, but it seems to have a mind of
it's own. Sometimes it works, then sometimes it won't. Mostly, it will work
for a few miles, then if I hit the brake or disable it, when I go to
reenable it, it wont work at all again.

I think I have a faulty steering wheel button switch again, or could it be
something else? Is there a way to diagnose this? TIA.

 

A good (read 'very expensive') scan tool should be able to read the computer
inputs that all the switches are connected to.
iirc you should be able to enter a mode where you can press each switch -
one at a time and see the result in the scanner.

btw- the Ion as I recall has an electrically assisted steering. What happens
with your front end alignment 'drifting' if you pull the fuse for the
steering?

Oppie

 

Had both the shop and OnStar scan for codes(a nice feature) , none. Just
brought the car in to the shop they said the cruise needed a software
update, there is a TSB on it. I'll try it for a few days and let ya know.

I haven't tried pulling the steering fuse. I attribute the drifting to the
overly sensitive electronic steering and the condition of the crummy roads
here. On a smooth road, my car will stay relatively straight. Never seen an
ION that held a hands-free straight line for as long as an S-series,
something to say about plain ol power fluid assisted steering.
--
marx404

 

It's either the brake or clutch switch. There is a separate set of
contacts for the cruise control on the brake switch. There is also a
switch on the clutch to kill the starter and disengage cruise. If the
contacts in either one of these are bad it will produce the random
symptoms you describe.

 

thanks Gyz, I will bring it to the attention to my techs to check these
things out.

 

Follow up to those following this post: Finally go the shop manager to ride
in the car with me and watch the TechII OBD reader as I tried the cruise
control. He found that the clutch switch was faulty and was causing the
cruise to not stay set or reject the code to stay on. They have ordered the
part, should get it Friday. All I could tell them was "told you so".