I got a '90 EF Hatch a few months ago and finally trying to wrap up the b20 swap. I have had a wiring nightmare trying to fix the previous owners hack job. I am currently working on the cooling system, and trying to wire up the radiator fan system but am not getting any signal to the coolant gauge. My question is if anybody on here knows the routing for the gauge wiring. I know there are the two coolant sensors, one by the thermostat that supplies the ecu with coolant temp, and the one of the head that is supposed to supply the signal for the coolant gauge on dash. I tried to hook a wire straight from the signal on the back of the dash to that sensor however that didn't work and I assume the wire from the sensor goes through some other thing to provide the signal to the cluster. Does anybody have a diagram or some info of how the stock wiring is? I plan on installing an aftermarket coolant gauge as well but it would be nice to have the output on the dash as well.