12v Constant for gauges, 2 issues, help!?
 

I finished installing a boost and AFR gauge in my car. I found the 12V constant source off a 16g wire on my ECU, conveniently located. I have two issues thus far.

1) The gauges overheat. After a half hour of use, they die, and you can barely touch them. Would an inline 10A fuse fix this?

And now....

2) In a rush to get things done, I accidentally grounded the 12v line, sparks flew (I know,, should have disconnected the negative, but was rushing), and now that line only reads 1.8 - 2v whereas before it was registering 12-14v (ignition off/on). Is this a broken relay?

Help!