Location of factory bus bar ground near instrument panel?

[ken4444]

I was looking over the '83 schematics to figure out where the wiper motor grounds (A reply to my build thread said the wiper motor grounds at the wiper switch), and I noticed that black #150 wire from the wiper switch goes to a gigantic splice which goes to a "BUS BAR GND" on the schematic with a saw blade-like icon on it (see pic below).   Is that correct and where is this physically located? What does it look like?   Does anyone have a photo?

If I can find a bus bar ground and clean it up, I might also be able to fix my fuel gauge problem AND my slow wipers.

Schematic:

http://www.73-87chevytrucks.com/techinfo/7387CKMans//Wiring/ST386_83_1983_GM_Wiring_Manual_CK_P_G_10_to_30_and_ST.pdf#page=9

[VileZambonie]

Behind the LH dash vent area and before the parking brake mechanism. 

[ken4444]

Behind the LH dash vent area and before the parking brake mechanism.

What's the easiest way to get to this?  From below?  Or above with the instrument panel out?  Or both?

How big is this bus bar?

[VileZambonie]

Under the dash unless the dash bezel and vent (if equipped) is removed.

[ken4444]

Under the dash unless the dash bezel and vent (if equipped) is removed.

Thanks for the details.  How likely is it that I can clean this assembly up and improve any ground-related problems?  This would seemingly be a must-do for any square body owner.

[75gmck25]

Cleaning up grounds is always a good idea, and having a single common ground point makes electronics much more stable.  When I installed a wide-band AFR gauge the directions were very clear about a single ground, because you are measuring such small voltage differences with the gauge.

FYI - on the older trucks like my '75 there is no ground bar.  They just grounded the instrument panel to a post on the emergency brake mechanism.

Bruce

[VileZambonie]

You sure about that? My 74 and 75 have it.