I have a Isspro mechanical fuel gauge in my truck. I never got around to hooking up the light for the gauge. I very rarely drive the truck at night. The question I have is..there are two prongs on the back of the gauge. Does it matter which one is the hot and which one is the ground? Neither of them are marked with a + or - sign. Also, I am wondering if you guys have had good luck using "add-a-fuse" connectors? FP gauge is the only after market electrical accessory I have on the truck. I was thinking of using the add a fuse connectors to get a power source out of the panel. Wondering if you guys have had good success using those?Or if I should use another way to splice and get power for the light.Thanks.

Yes, I have used those piggybacks before with no problems. Just make sure you don't overload them. If your just using one to light a few gauges you will have plenty of amps to spare those little lights draw next to nothing for power. Can't really comment on the wiring of the gauge light without seeing it. Maybe a picture would help a little. Do they look identical in the way they are connected to the back?

It shouldn't matter on + or -. Power in and ground out. The bulb won't care which way it goes. I tried it both ways on my isspro gauges. Didn't make a difference. Those piggy backs work great for gauges as they take hardly any power.

Use either wire for the hot (+) side of the blub. It's a DC system so it doesn't mater. I took my power of the orange wire at fuse #5. That fuse is after the light dimmer switch. Wired that way you will be able to dim the light and it will have a 5amp fuse protecting the circuit. This is how I did my 4 gauges.

Since I used a proper adapter for the stereo it left me a pigtail for the lighting for my gauges so I tapped that wire and took it back across the dash for the lighting. Problem solved.

Good instructions here. pictures 25,26 and 27 http://www.dieselmanor.com/diy/CMS-G2gauges/CMS-gen2gaugeinstall.asp

The wire that is tapped in those picks is the tan wire that goes to fuse #5. If you tap that wire you will need to put an inline fuse between the gauges and head light switch.

The wire that is tapped in those picks is the tan wire that goes to fuse #5. If you tap that wire you will need to put an inline fuse between the gauges and head light switch.

I'm running a 5A fuse. Also running a fuse between the 12V source and the pyro.