OK, this is driving me nuts!
Same laptop, different car. Mastach cable still wasn't working today, so I made a patch cable using the single resistor, regulator and a few caps today, and still nothing (actually soldered the components right to the chip

). Even tried the large regulator and using an old cell phone car charger just in case the laptop suddenly decided not to send 5v through the 7/8 pins (still nothing), and even added another cap bridging the 12v and ground, but it started to pour outside and had to lay it up for the night before I could try it this last time.
I tried using both TunerProRT and ALDL_test, both cables, 2 cars, nothing, nothing, nothing
Any suggestions now? I know the laptop port is working fine since I use it to send programs via rs232 to the CNC machines at the shop.
Guess I'll have to break down and buy a pricey cable

but them I'm afraid things will still be the same...