So replaced some dead bulbs in my instrument gauge cluster, and found that when i reinstalled everything i noticed a few bulbs were out and the speedo wasnt working.

I took the cluster out and tried to fix it, i got the bulbs to light up, but now when i turn on the car, the tach goes to about 2300 rpm and stays there... and the speedo is still not working... temp gauge and the gas gauge work just fine...

 

Did you put each screw back in the exact spots they were in originally?

They have a certain amount of electrical impedance. I made the same mistake and my engine coolant temp gauge didn't work until I put the proper screw back in.

 

I wasnt able to put the exact screw back in the exact place, but I put the right type in its place... Are you saying that the screw of the same length and thread type, would have a different impedance from another screw of the same length and thread type?

 

I'm not 100% certain, but I'm guessing yes. I had to the put the EXACT screw in or else that particular gauge wouldn't work properly.