COSTAR-Tech Forum

Hello,
I have a 2007 Cadillac STS. My Co-Star is not cutting off my radio to receive phone calls, but I can see light changes in the onstar controls in the rear view mirror when I have an incoming call. My question is that I had to remove the LOW Speed connection out of the J4 Plug and Place into the J1 plug as directed below. Do I need to indeed splice the wire so I have the original connection in the J4 remain, and one in the new J1 with the splice? Any help will be greatly appreciated. Directions from the manual are below. Thanks, Dave


In cases where the GMLAN LOW SPEED connection is located on the BLACK J4
connector, and not on the white J1 connector, it is necessary to wire this signal into the white
connector so that the BlueSTAR module can communicate with the radio. This is accomplished
by using the included t-tap to SPLICE the jumper wire to either GMLAN LOW SPEED signal
located in J4-1 or J4-7 (usually green wire), and routing it to the GMLAN LOW SPEED signal on
the BlueSTAR connector, J1-1. If both GMLAN LOW SPEED signals are populated, OR all four
GMLAN HIGH SPEED wires are populated in J4, you MUST leave the BLACK J4 connector
plugged into the onstar module to insure that the GMLAN bus is carried on to the rest of the
vehicle.

If you have two wires in the J4 connector for the low speed, then they must be tapped so that the data bus continues to other vehicle components.
The onstar module is used to connect the wires to each other. That is why it must remain installed into the onstar box. Also the same with the high speed gmlan data bus (two wire bus)

If you have only 1 wire going into J4 (unlikely) then you are ok to simply move it to J1.

Thanks for the reply. I only had 1 wire in the j4 and moved it over to J1. My phone syncs up, and my mirror buttons work fine with my phone, my stereo however is not detecting the call or providing speakers or mic for the calls. Any advice would be greatly appreciated. Dave