A2 - AUTO TRANS 12V. IGN - NOT NEEDED
B2 & B3 - NOT USED 3500HD
C2 - PARK/NEUTRAL SAFETY SWITCH - NOT NEEDED
D1 - ABS DIAGS GOES TO DLC - 3500HD ONLY
Are there terms on the firewall conn. for any of the above terms?
That metal box is the speaker amp.
The receiver is a black plastic box on the other side of the metal bracket that the amp is mounted to.
The photo I posted with an arrow is one of your photos. 3rd photo post #4.
It's there or your keyless would not work.
First of all, if the other door locks...