I just bought a tach from my Volvo mechanic that I'm hoping to fit into my 93 240. I was told it came from a 100 series, it has 2 lengthy white wires, one short white wire which I see goes to the bulb, and 2 short black wires. One has a ring crimp which I imagine is ground, but I'm unsure of the res...

My friend has had the computer chip that controls overdrive burn out on his 89 740 standard trans once, I'm not sure if the auto trans has the same setup but getting that tested might help. Or a simple check is to visually inspect the wires next to the shifter mechanism under the car. I had overdriv...