Ok ive got the Defi temp gauge.. I hooked it all up the correct way ( I think) I went by what the manual says and when I turn on the car the gauge does its little thing then goes right to 300 and ticks to bout 280 then just back and forth. I know its not working correctly cause my cars not 300 and it ticks pretty damn fast.. Im not sure whats goin on.. If anyone has any ideas on what to do please let me know! Thanks

 

I've not worked with the Defi electric temp gauge, but it sounds like maybe the ground wire isn't connected or at least not connected correctly. Another thought, did you use the Defi sending unit? I doubt that it would work corrctly simply attached to the factory temperature sender.