I have an '84 camaro that came with the instrument cluster with the idiot lights and big fuel gauge. I got a cluster with a tach and all gauges from an '86, and when I installed it, all of the gauges work except for the temp. I did relace the temp switch(for the idiot light) with a sending unit(for the gauge) like I should have, but the gauge shoots all the way up when the car is running. Any ideas as to what is causing the problem?

 

Id say replace the sending unit on the driver side head unless you already did, or if its going all the way up im pretty sure that means its a short. Possibly an open cuircit and if so someone will correct me, but im pretrty sure its a short

 

It's shorting somewhere. It should pin when you are cranking then settle down to whatever it's supposed to read.