OK, after sone testing, I determined that the channels were wired backwards, so sound in the right was coming out the left and vice versa.
I decided I'd use it as an opportunity to redo the job more cleanly and neatly, so I traced the relevant wires on the harness to their respective pins on the tape deck's main board (the thing the EQ buttons/display and tape mechanism connect to) and soldered the wires of the aux cable to the underside (this time taking care to make sure left and right were correct).
I also soldered in a pigtail for a switch, so I can hook one up later if desired.
When not in use, I pull my dummy tape out and coil up the aux cable away in the ashtray.
Why didn't I do this sooner?
c
I decided I'd use it as an opportunity to redo the job more cleanly and neatly, so I traced the relevant wires on the harness to their respective pins on the tape deck's main board (the thing the EQ buttons/display and tape mechanism connect to) and soldered the wires of the aux cable to the underside (this time taking care to make sure left and right were correct).
I also soldered in a pigtail for a switch, so I can hook one up later if desired.
When not in use, I pull my dummy tape out and coil up the aux cable away in the ashtray.
Why didn't I do this sooner?
c