Hi everyone, so I just took my 8 on a roadtrip to Vegas (~4 hour drive from my house) and since there was no traffic I naturally set the cruise control.

However, about 3 times on the way there, and twice on the way back the cruise control decided to suddenly disengage. It was as if I pressed the "cancel" button, but I didn't touch anything. The "cruise main on" light stayed on, and I each time I was able to press resume to bring it back as if nothing had happened. It may or may not be a coincidence, but it seems like it happened at times when the car was "disturbed", like a small bump in the road or starting to go up a hill.

I can't seem to reproduce the issue consistently, so I'm really not sure where to start looking. Any ideas would be appreciated. Thanks!

Edit: I have a 2005 Base model with 96,000 miles

 

Did you happen to hit or tap the brake pedal?

 

Nope. I'm well aware that hitting the brake or clutch will disengage it, and human error is always a possibility, but since I experienced this issue 5 times in one round trip makes it seem highly unlikely that it was my fault.

 

Testing and Inspection


CRUISE CONTROL SWITCH INSPECTION



1.Disconnect the negative battery cable.
2.Remove the driver-side air bag module.
3.Disconnect the audio control switch connector


4.Inspect for resistance and continuity between cruise control switch terminals B-C using a tester.
•If not as specified, replace the cruise control switch.

 

I'm a manual transmission RX8 owner in Europe and I repair car computers by the way.
I'd like to install cruse control to my European car (which was very rare here).
I already modify the PCM configuration and put the cruse wires on.
Now I can switch the yellow "Cruise Main" light on on the cluster, but it doesn't keep the speed and the green "Cruise" light doesn't light up, even though the fallowing: break switch OK, clutch switch OK, cluster led test OK (there is green cruise light as well).
Maybe the instrument cluster configuration is incorrect, I tried to rewrite asbuilt data in the cluster, but there is a byte, which I can't modify, the cluster doesn't accept it.
I need a whole eeprom dump from an RX8 cluster, which has cruise control (L56R= 93c56 in 16bit format)
or if somebody has any idea, what should I check, please let me know!
Cheers!

 

Have you ever figured out the problem ? I have the same issue with my 2005 Base model and the cruise control disengages very often. The green plastic pieces on the clutch and brake pedals are intact and i can tap on the pedals slightly without disengagement. Did replacing the cruise control switch fix it ?

 

Did you try adjusting the switch?

 

 

Team how exactly does one adjust the switch ?

Ok so I sourced out another used Cruise Control switch, problem persists, possibly less but it is still intermittent.

 

https://www.rx8club.com/series-i-tro...switch-190708/

 

Actually I wasn’t thinking it through and only responded directly to you asking about the clutch pedal switch. You would likely be experiencing moments with it not cranking if it was the clutch switch. It seems more likely to be a brake switch or wiring issue for cruise control. Potentially some other things, but I’m not entirely sure because I don’t have that much experience with the CC feature. When I saw your post in the other thread it made me realize this. Most people have no-crank issues with the clutch pedal switch. I could see it maybe losing signal intermittently at the clock spring/steering wheel connection as a potential issue.