Gordon Killebrew

Rich, the cause of your cluster problem appears to be a poor ground and clutch wire #153. It is a cluster lighting ground. It is cavity D3 in the cluster's large 32 pin connector. The black/white stripped wire goes from the cluster to the ambient override sensor located under the left dash. The "dime sized" sensor is attached to the harness wire back where it goes through the firewall to behind the battery where ths engine and forward lamp harness is attached to it. The ground is attached to the top left transmission bellhousing bolt. The simplest fix is tc remove the left lower plastic dash panel {the one with the light in it). Locate the ambient override sensor. Using the black/ white stripped wire, DON'T CUT THE WIFE, just remove a small amount of insulation from a spot. Solder one end of an 18-gauge wire about one foot long, to the black/white stripped wire. Cover your solder joint with electrical tape. On the other end of the one foot wire, remove enough insulation from the end to expose the wires to fit into the clip end of a ring terminal. Put a lock washer under the ring terminal and attach it to the door pillar, which is steel and will give you a ground for your cluster. Now I ask the question: Did all of the bellhousing wires get reattached correctly? You might want to check them!

The transmission shifting too quickly is usually a misadjusted throttle valve cable coming from the transmission to the engine's throttle body linkage. To adjust the cable, (engine not running) push in the cable lock where the cable attaches to the air plenum. With the lock pushed in, slide the cable's plastic sleeve rearward. This neutralizes the adjustment. Replace the lock and manually open the throttle I nkage to wide open position. You will hear a clicking noise. The cable is self-adjusting and the transmission should shift correctly now.

I needed to install a new circuit board to fix the tachometer in my

1976 L86 coupe. I pulled the dash and accidentally installed the part incorrcctly. However, afterwards the clock was working when it wasn't before. I puf.ed the dash agan and installed the part correctly and the tach is now working, but now my dashboard lights, dashboard lights for gauges and clock arc not. My headlights, taillights and blinkers are working correctly. I have checked all the fuses and they are fine. Could you recommend what I can try next to get everything working again?

Skip De Los Santos

Aldan, PA


Skip, sounds like you are becoming well versed in 1976 Corvette dash cluster removal and installation. Probably the easiest place to check for cluster lighting power is at the cluster fuse itself. Locate the cluster fuse in the fuse panel. Connect the test light ground clip to a known good ground. Use the test light probe to touch the cluster fuse with the parking lights on. When the headlight knob is turned to control cluster brightness, you should see the test light change intensity. To begin with, if the test light is lit we know that the headlight switch is supplying power to the cluster lights. If the intensity changes, we know the headlamp switch rheostat is working properly. If there is no light from the test light and the fuse is good, there is an open circuit from the headlight switch to the fuse. This could also be due to a poor connection at the headlamp switch, which by now has been disconnected a few times. The gauge lighting uses multiple lamps with gray colored wiring. It doesn't make sense that all of them would be affected. If the test light is lit, chances are there is a ground issue, although th s doesn't make a lot of sense. The speedo/tach cluster uses a separate ground from the gauge's cluster ground. The speedo/tach cluster has a dedicated ground connector at each gauge. The center gauges cluster has another ground point so it seems odd that all gauge lighting is affected from a poor ground. I believe that you'll find the problem is a poor connection at the headlamp switch or a failed switch. Good luck!

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