84 z31, taking the dash out. I have almost everything disconnected. I can see the back of the speedometer and the cable going in, just cant see a way of getting the cable off. Any hints ?

 

I've never messed w/ a Z31 dash, but I imagine an 84 isn't much different from a 280zx. There should be a large plastic ring around the end that you twist loose (connecting to the speedo / back of gauge cluster). The 280zx has a 1ft extension cable that unscrews right at the firewall.

The usual removal method requires getting upside down w/ your head at the pedals and legs up on the seat, and stick your arm up to unscrew it.

 

There's a plastic clip you have to get you hand in there press on both sides and it pops out, not easy but doable. Minus a little skin and half a dozen cuts later. Better than last week, nicked an artery 8 stitches and about a pint of blood later the VA had me fixed up, kinda set me back a week. But now there isn't a bit of the interior left, just sheet metal and the harness in a heap.

 

Here's the connector, as you can see there's a place to press that releases the 2 tabs on both sides.