I just hooked this up tonight!
Crazy as I just did this an hour ago. What I did was hooked it into my dimmer switch for my interior lights so it could be adjusted.
steps to do that:
1-remove the trim around the instrument panel by simply pulling on the trim and it will pop out, be careful not to break but will need to pop it out.
2-then use a 6 mm and loosen the 3 screws that hold the light switch and dimmer swith in place.
3-pull the light switch/dimmer unit out as one unit, you will have to pull a little hard to pop this out
4-then you will insert the positive wire into the top wire whole in the dimmer switch.
5.assuming the other wire is grounded you should have power to the lights in your instruments, test before putting switch back in
6. just pop the switches back in place and you should have a working fully dimmable gauges.
be sure to test and make sure is working before putting back together.
good luck!