I just installed a si cluster with tach for a 91 hatch to replace the dx one. i had an aftermarket tach hooked up with the wire patched into the wire coming out of the ecu. now my tach in my gauge cluster is not working??? any ideas? I checked all the connections, wiped em down, replugged everything back in and nothing. should i check if i'm missign wires??? if so, what wires??? my aftermarket tach works fine.

 

My friends does that. Why do you need 2 tachs anyway?

 

I don't need two tachs. I need the tach in my dash to work, not the aftermarket one. but the tach in my dash is NOT working and the aftermarket one is. there is one wire missing from the smaller grey plug. should there be a wire in there?