Ok, apologies if this has been answered. I have an 1986 T/A with an electronic speedo (85mph cluster). I suspect my engine temp gauge is broken. I replaced the coolant switch (LG4 car) and inspected the wire and didnt really find anything there. I am going to pull the cluster in the car and ohm the wire out between the connector at the dash to the switch on the block to confirm the wire is bad here. I find a good many 145 mph clusters and would be interested in having one of these instead but, my question is will it be plug and play? Would the buffer box need to be changed with it?