g s i ???

[sportpig]

What do they mean on back of instrament cluster ?

G.    ground
i.      ignition

S

my temp gauge keeps bottoming out with ignition o ???n there is tension. I'm gonna run seperate wires. really want to do it tonight thanks.

[eaglefreek]

On a starter solenoid it means "start" for when you put the key in the start position. Not sure if that's what it means on the cluster.

[vangremlin]

I looked at the back of an instrument cluster and also the 1981 TSM.  There are two "S"'s stamped on the back of the cluster.  One is next to a copper strip that goes to the 4th peg in the vertical strip along the left side (looking from the back).  This connects to the temperature sending unit.  The second "S" is stamped next to a copper strip that goes to the third bulb from the from the left along the top of the instrument cluster.  This bulb is for "battery" indicator. 

So I'm not sure what the S stands for.  If you are running a new wire for the temperature gauge, it looks like the 4th peg is the one you want.

Good luck!

[sportpig]

The forth peg is the only peg with power . on the circle one none have power. warning lights come on .idk ? Seems like the gas gauge works.

[vangremlin]

The forth peg is the only peg with power . on the circle one none have power. warning lights come on .idk ? Seems like the gas gauge works.

I should have been more clear, i meant the 4th peg from the bottom.  The 4th peg from the top seems to be the power feed.  The fourth from the bottom seems to be the feed from the sending unit, which provides variable resistance.  From the circuit board on the back of the cluster, it appears that the gauge gets power from the "I" (which should have power when the ignition is on) and the feed from the "S" (sending unit) which has variable resistance, which determines how high up the needle goes. 

Clear as mud?

[sportpig]

Okay what I will do then is try to chase that wire or bypass it to the sending unit.  Ill keep in touch.  Pretty sure that wire isn't a green black at the cluster but either way Ill flat out run a wire from the cluster to the sensor.  Thanks man a lot.

[sportpig]

  Ok this is where I'm at.  With key on I have power( vertical pigtail ) on the first or top wire.  That wire is white w/black , and the forth one from top down which you said is the feed.  That wire is purple w/white.  Nothing else on that strip has power to it.  On the circle piggy nothing has power.  Your help is Godsend.  Thank you.  You could email me pics of schematics if you could.  That might help idk.