Odometer/gear selector problem, Help!

My Odometer / gear selector goes dark intermittently.  Sometimes by pushing at the top center of the cluster I can get the display to light up, sometimes. 
I think it has to do with the 20 pin plug at the top of the instrument cluster.  One of the pins is not quite making the connection all the time.  Fiddling with the wires with the cluster removed does not help me.  I cannot get the display to fail reliably.  It is either on or not. 

I have unplugged and replugged the connection.  I have use a cleaner to try to clean the connections.  The problem persists.

I don't want to take this to a dealer being an intermittent failure.  (I'm sure it'll work fine for them)

My question is, on a 2002 1500 Avy, which pin on the plug is the odometer/gear selector? Maybe somebody knows which wire it's supposed to be?  (color)
Does the wire bundle need to be seated under the dash in any special way?  I doubt it but you never know.

Just a thought but it sounds to me like something loose in  the circuit board rather than the plug, like maybe the board on  the main board, you can disassemble it and carefully look at it, and resolder if needed.


Didit

Well I'll give it a look.  But the question remains, anybody with a manual that could tell me which point belongs to the odometer/gear selector?

What's been interesting after my last attempt to fix it is that the indicator works first thing in the morning, it goes for about15-20 minuts and then goes dark for the day.

Had all the instruments fail and recover on its own on my 2013 and the dealer was not able to locate any cause.
Seems like something Chevy could be aware of ad put out a service note.
Waiting for another fail.