smittycm

I'm trying real hard to fix my instrument cluster issue in my 66 coupe. The oil, temp, and fuel guage are the only guages giving me trouble. They flicker on and off, or they start dancing around. I'm sure it's a faulty ground somewhere. I also heard it may be a faulty ignition switch, but I'm leaning towards the ground. First thing I did was replace the constant voltage unit. Next I sanded down the paintwhere the constant voltage unit grounds to the dash andtightened the screw down real good. Nextthing I thought I'dcheck was the engine-firewall grounding strap and I can't find it. Is it hidden underneath? I read it should be connected betweenone of the cylinder heads and the firewall. I looked all over the engine compartment from above and I can't see any grounding strap anywhere.I seethe ground going from the battery to the engine block and that's it.Do you think the PO moved the grounding strapelsewhere? Could he have removed it all together? If there was no grounding strap, wouldn't I have several more issues with my electrical than just my guages? How can I check to see if the frame/body/firewall is grounded good enough?Whatdo you guys think?

highhilleer

IIRC the stock location is from the pax side head to the firewall like you mentioned. The stock grounding cable is a flat strap that looks like woven wire. I would install one just to be sure you have good a ground going to the instrument panel.

JamesW

The 66 instrumentcluster has a ground wire thatconnects from the panel to the dash brace behind it. If that is checking good, then you're good to go. If your instrument cluster lamps are working ok, then you don't have a ground problem.

1) Check the wire thatdaisychains from the CVU to the 3 gages to make sure it doesn' t have shorts and is securely connected.
2) Check and see you have a consistent 12V coming into your CVU.
3) Test your new CVU to make sure it's working properly. Hook it up to a 12v & ground, and put a meter to the output to see it's putting out 5V. It's not uncommon to get a bad replacement CVU.





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