Where is the “Relay Block-Body”


I am trying to locate the “relay block-body” to install an overdrive inhibit switch on a 2001 Chevy 3500 with an Allison trans. GM TSB 02-07-30-051. It would seem to me the RBB would be the body/block that is located on the driver side near the floor and kick panel. A few relays 6-7 open slots for plugs etc. BUT I looked at some other TSBs and it would show a picture of the aux fuse box located on the far lower left of the dash with the cover almost flush with the door. I need to know which box it is and which connector spot is the #4 slot. Also the plug need for the switch is a gm15306105 and looks to be a 6 pin plug. I looked at some of these plugs on the truck and can not find any designation for which pin is which. I need the “E” pin. Anyone with a manual and could look this up would be great!


Thanks Brad

I think what you are looking for is located to the left behind the brake pedal and has a black cover with a nut in the center. Pull the nut off and take a look. The plugs only fit in a certain receiver by design.

If this was posted in "Ask the Techs" I'm sure that you could get the answers you need.

You could also PM GMCSID, Cobra3737, or DMaxalliTech