Just put in a DIY FCD and it tested fine but now the coolant light and buzzer comes on seconds after tuuning key to on. I triple checked all the connections on the FCD and ruled that out . What else can make light come and what should I check ? and is the boost sensor curcuit have anything to do with it. And yes it is full of coolant and the temp is fine.

thanks

 

If you remove the FCD, do the lights still come on? If not, then the problem is with the FCD.

 

The light still comes on when I unplug the boost sensor. Maybe its just a coincidence but its sure funny. I drove it pretty hard the last time I Had it out, then I screwed with FCD then I started it. The overflow was low but the at the rad cap was full. I topped up the overflow but the light still came on. Hmmm.