6. Here are the parts taken from under the steering column. It took only a few minutes to remove these items, and it gave us the opportunity to clean them and the area under the column.
7. To avoid scratching the paint on the column while removing the instrument cluster, we draped a small towel over the column and down under the dash.
8. Here is one of the four dashpad attaching points under the dashpad. If your GTO is not equipped with a padded dash, simply remove these screws using a stubby Phillips head screwdriver. After you remove the screws under the dash lip, the pad can be gently pulled free.
9. With the screws/pad removed, we gently pulled the housing up and out and let it rest on the towel, and then reached behind the cluster to unplug the instruments and light bulbs, and unscrew the speedometer cable from below.
10. There are three cables under the dash that operate the heater/defroster levers. They are attached to the control switches on the instrument cluster and the levers on the heater box. Here is an example viewed through the glovebox hole. We disconnected them at the heater box before trying to remove the cluster.
11. We were familiar with the wiring, but if you're not, label each wire or light bulb as you remove it. This might look intimidating, but once you start, you'll see that it's helpful and easy. Remove the cluster and heater cables carefully so you don't scratch any paint.
12. The original tach has the red plastic insulator on the coil-wire connector. Unlike the new replacement, this is the only wire connected to the factory tach. The heater control cables are at the top.
13. Several small screws hold the gauge housing to the cluster. Once we removed them, the metal case that houses the gas gauge, alternator warning light, speedometer, and tach-ometer was the next item to detach.
14. Using a small screwdriver, we removed the tiny slot-head screws holding the tach faceplate to the meter movement. Here you can see the mounting points. We were careful not to scratch the paint on the original face. Also, we did not use a chemical cleaner on the faceplates—it smears the numbers. A soft, dry cloth removed any dust.
15. With the two screws removed, we slightly lifted the faceplate and carefully moved it over the original needle and free of the meter movement. We will reuse the original face and screws on the new tach movement.
16. The factory tach housing is secured to the cluster housing with three small screws as shown. We lifted it free of the cluster and out of the way.
17. The replacement tach movement can now be secured with the original screws. The white wire is a ground that is secured with one of the tach mounting screws. It is supplied with the replacement tach. The spade connection on the right goes to the key-on power source at the fusebox, while the coil wire attaches to the stud on the left. It couldn't be simpler.
18. The original tach faceplate was carefully replaced over the needle and secured with the two factory screws. The assembly can now be reattached to the metal cluster housing and reinstalled.
19. This is one of the levers that activates the heater-box controls. They are made of plastic, which becomes brittle with age. We repaired a broken connection point with Super Glue and JB Weld, as seen at the bottom right. While the assembly is out of the car, we lubricated all the moving parts with a quality white-lithium grease. We used Justice Brothers' aerosol grease to get into all the tight places.
20. To show that the replacement tach fits exactly as the original, here's a profile of the tach on the left and the temp and oil-pressure gauge connections on the right. As you can see, clearance is not a problem.
21. After reinstalling all the components as they were removed, we re-connected the battery and fired up the engine. Yes! That gorgeous yellow needle jumped right up. The engine's pacemaker is alive. If we can do it, you can do it.