No grounding point on the back of head unit (Pioneer KEH-M7000RDS)

[Hongkongphooey]

I've been experiencing a recurring problem with my head unit cutting out at random times.

Having got the removal keys and taken a closer look behind the head unit I've discovered there's no grounding rubber/screw on the back 

A few questions therefore:

(1) Where can I get a rubber/screw to make a connection to the ground wire on the back of the head unit?
(2) Will there be a wire somewhere (other the cables I can identify; those in the ISO loom, the antenna, the CD changer) that is the ground wire? What will this look like?
(3) Should I just pick up a cheap replacement head unit on Fleabay that has the grounding connection on?

All help appreciated...this is driving me nuts

[Hongkongphooey]

Maybe I should ask this question differently....do all Head Units have a grounding wire connection on the back or is this somehow integrated into the ISO loom?

Quite a few on EBay don't seem to have a dedicated grounding point on the back from the pics I've seen.

Ta

[Hongkongphooey]

Answering my own question here but hopefully this will help others.

It appears on these old Pioneer HUs the Ground Wire goes into the ISO plug so no need for a separate ground connection on the back of the HU.