phomat

Bought a Chinese Star Diagnostic multiplexer with hard drive. Of course, there were no instructions. Hooked it up to my computer and the OBD port, and nothing happened. Doesn't seem to be getting power. Not sure where it's supposed to be getting the power from; the computer or the OBD port. RS-232 ports don't appear to have a power output, just a ground and a "ring indicator". Where do these units get their power?

Rudeney

Power to the multiplexer is supplied by the OBDII port. There should be an LED on the multiplexer to let you know it is receiving power.

phomat

Thanks. I actually figured that out last night, and knowing that tried hooking up the unit to my other cars' OBDII ports. It didn't respond to any of them either, leading me to conclude it's either a defective cable or unit. I'm about to try to test the cable. Unfortunately, while I know the #16 pin is the 12v source on the OBD connector, I haven't a clue which of the approximately 60 terminals on the other end of the cord correspond to that. Guess I'll test them all.
Thanks for being such a great source of information; you truly are a Guru.

phomat

Cable is good. It's the unit.

Rudeney

Dang! Cheap Chinese crap!

MooksM275

I will tell you they are not plug and play like this. You have to go through certain settings on your computer to get the thing to work. Even small things like running VM as adminstrator can make a difference. Took me a week of working through it to finally get it to work. But at the beginning, same issue as you with no power to unit. Email the supplier and they should be able to work through it with you. They can even run screen share which is fine if you use a dedicated laptop with nothing personal on it.