Just installed issopro ev2 piro and boost gauges, 

Questions what fuse or wire ignition should I tap into?

#2 what wire can I tap into for dimmer....thank you for the help.

Any fuse that is keyed hot. Take a test light and test for fuses that light up with key on and go off with key off. 

Ok what about a dimmer circuit use the ashtray wire?

I've got a aftermarket stereo (Kenwood MP3 player) so the panel light lead was left open so I took it over to the gauges. Some use the ashtray light.

Ok thanks.

don't splice into existing wires..... just a new headache for later.

 

 Use fuse block add a circuit.  

 

you can get dimmed voltage on fuse 5 and fuse 14 ( i think) is already called gauges. 

 

 

Thanks just what I did.