I have the typical instrument cluster issues that plague the 84. Mostly it works but the Tach is usually at zero or intermittent. Occasionally I need to use the left fist on dash technique. I intend to have it rebuilt soon.
Also my cruise is totally non-functional. Now I've read somewhere that the cluster can cause this issue on C4's. The question is concerning this. The cruise on the 84, I believe, is an older design than on newer C4's. So could this still be the case? Should I just wait until the cluster is rebuilt before trying to fix the cruise issue?
Thanks for any help/opinions.
Wayne

The speedometer signal for the cruise control has to go thru the cluster before it gets to the cruise module. If there is a problem with the cluster, the cruise will not work. Same problem with my '85. Once I got the cluster rebuilt, the cruise came back on-line.  

Thanks for the help Adam. I will have the cluster rebuilt before checking any cruise issues.

I'm not saying that the cruise might not have other problems, but I do know it will NOT work if the cluster is on the fritz, so that needs to be addressed first.

That's what I assumed. No telling what else might be wrong be since the cluster needs fixing anyway, I will do that 1st and see what works after that. Thanks

my 84 has the same problem. getting ready to have my cluster rebuilt by the person that Joel recommended. thanks Joel. i hope my cruse will work after this is done.

So if I understand this right, if there is a problem with the LCD portion of the speedo, then the cruise control won't work?

Not necessarily. The actual LCD display could have bad segments that won't light up, but would have no effect on the operation. However, if one of the boards, or the module of the cluster is funky, then you could have a cruise operation issue. A LOT of cluster issues wind up being bad solder connections, and bad external grounds, but there are other problems that they have also.

Thanks for clearing that up for me Joel....I have some bars between 35 - 65 that have quite lighting and I'm hoping to pull mine and send it off for repair soon. It's coincidental I guess that my cruise went out right after I lost those segments.

|UPDATED|2/3/2013 5:36:38 PM (AZT)|/UPDATED|

For anyone intending to have their instrument cluster repaired, be aware that IF you have segments of the display that do NOT work/light, the LCD panel itself is bad, and that is NOT part of the original quote for repairs. The LCD panels will cost extra to replace...and they ain't cheap. I had ONE segment on my tach display that dint work, but I wasn't concerned about that....it sure wasn't worth the extra $$$$ quoted to replace it. The repair service will only take care of any electrical issues with the cluster. They CAN replace the LCD panels if you want them to...for a price.
Just thought I would mention that....