My Boy has a 89 Civic DX with a cluster with no tach, its a 5 speed, So we when to the junkyard and got a Tach cluster from a 89 CRX and the cluster plugs up but the one from the crx has this white box that the DX civic doesnt have plug for. So when I connected it, this is what happened, The check engine came on and the fuel and temp gauge didnt rise but came all the way down and the lights didnt work from the dimmer.
How can we go about trying to fix this.

 

that white box is a speed sensor amplifier. if the cluster you have has one, it is either a 90 or 91..88-89 cluster didn't have them. i had a 90 cluster that i wired into my 89 and i just took the box out and was fine. check which code is being thrown..pull up the passenger side carpet and look at the ECU..count the number of blinks..that is the code. look it up in a service manual or post it up on here and someone will help. good luck.