Just an update: tried splicing the grounds differently (after looking at the wiring schematic) - still didn't work
so i bought some 8-pin sockets at Radio Hack and cut up the TrailTech harness.
hooked up everything normally (as in - no spliced grounds other than factory) and it works great!
My tach was bouncing around a bit so i called trailtech and they attributed it to a 'dirty signal' and offered a couple suggestions:
!.) wrap the wire around the spark plug wire only 4 or 5 times
- same result
2.) connect the + lead to the + input on the coil
- same result
so i still have a bouncing tach
i just finished hooking up the speedo sensor but havn't had time to test it
drilled a hole in the rotor base for the magnet and hacked up the dust shield (?) around the rotor to hold the sensor
i think i'm going to ditch the dust-shield and make a bracket
the installation instructions only have you calculate the circumfrence of the tire for the input of the compute (you say your Circumfrence is __ and it figures out the rest).
wouldn't it depend on where you install the sensor in relation to axle or center of the wheel?
perhaps i'm looking too far into this...
oh, and in the process i discovered the brake line was seized on the caliper (and the PO had already broken the bleeder) - so i had to swap the ends of the line. I will see if my local place will make me a new one.
also recieved my EBay tach-plug