That is what I did. It eliminated the need for another switch on the dash and works great with a couple of LED lights mounted on my under dash panel.Courstesy lighting has it's own ground which comes from the side of the headlight switch. Connect the gray wire to that, the red is hot. When you turn the headlight switch to a full stop it will turn on the courstesy lights. Good Luck
if you want get some led fixtures i got some from a Marine supplier, i used a circuit that wasn't being used like the electric choke for me, hooked the power side to the fixture and the ground to the headlight switch used the dome light part of the headlight switch it works on switching the ground. the led's don't pull much.Looking to hook up some courstesy lighting under dash. The Courtesy lights have - red / blk wires (self explanatory). Ron Francis harness courtesy wires - red / grey wires. What do you do with the grey wire?
The choke sircuit is only hot when the ignition is on. That sort of eliminates being able to flip on the courtesy lights to get your keys organized and into the ignition in a dark car! Do it as you wish but I recommend a constant hot feed like the radio memory....i used a circuit that wasn't being used like the electric choke...