Still trying to find someone with info on what wires need to be added(and where) when switching from an idiot light cluster to an Rally Gauge cluster(other than new temp and oil sensors)without a whole new harness

No wires have to be added, Two wires have to be switched and one has to be cut. When I changed mine, I just installed it and started the car. I realized right away that something was not right. I removed the new cluster and laid both of them face down on the work bench. By following the printed circuit lines I could see where the difference was. I switched those two wires and re-installed the unit and it works! Then I noticed that when starting (when the key was in the start position) the temp gauge pegged to the high side. In the idiot light set-up this lets you know that the light is working. It is a green wire in the harness. Just snip this wire (I think that there are two green wires in the harness so make sure you have the right one or be prepared to repair if you cut the wrong one). There was a FAQ on this on the classical pontiac web site. Hope this helps.

Hank350,do you have a diagram or can you tell me which two wires to switch,I dont have a complete unit to set side by side.Thanks Rod

Rod,
I can't remember which wires to switch and I'm not sure if they can be seen without pulling the cluster. I'll look under the dash to see if it is visable. There is a thread on this in the FAQ section of classical Pontiac (www.classicalpontiac.com) That's where I found out about cutting the wire that was pegging the temp gauge when starting. More later, Hank

Rod,
I looked under the dash and I can see the wire nuts but can't see the color of the wires that were switched. If necessary, I could pull the cluster but I'm not sure when I might have the time to do that. I still have the old cluster and could e-mail you pictures of the printed circuit on the back if that would help. I think one of the wires is from the Alt. light but I can't remember what the other one is from. I checked the Classical Pontiac site and it seems that their archives section is unavailable right now.
More later, Hank

Hank,thanks for all your help and if you can send me pics of the old cluster that might help,but please dont remove your dash just to look.I will get this figured out,Iknow we're not the only ones that have done this.Thanks again.my e-mail is [email protected],in case you get some pic's....would like to see your car as well.Rod