Need help with tach!!

[Elliot]

Here is what happened...
I decided to remove the HVAC from my track car. pulled the dash and and the centerconsole. In the process of removing the HVAC unit. I remove the OBC and the wiring harness. That wiring harness is connected to the yellow connector in the cluster. All I have now are the blue and the white connectors.

My tach doesn't work. I checked the SI batteries and both reads 2.8V. Did throwing away the yellow hurt my tach?

Elliot

[accident]

I think so. My car has no OBC and still has 3 connectors on the cluster

[Elliot]

any one else?

[Elliot]

Can some one remove the yellow plug from your car and check is that the cause for the dead tach?