You can "hotwire" the headlights, like a fuel pump. On my '87 GN, with it running I had 13.65 volts at the headlamp socket, showed 14.1 on scanmaster, so .5volts I wasn't too worried. But.......
On my '81 El Camino (Which looks to have much smaller gauge wiring) had right at 12.00 volts with it running, and showed around 14 volts on the autometer gauge, a loss of 2 volts! In addition to purchasing the 4656ST silverstars, I bought the materials needed to make a hotwire kit. I ran 10 gauge wire from the back of the alternator to a relay (which I still need to add an inline fuse
), and then 10 gauge wire to the headlight sockets on each side. Used 10 gauge ground for the relay also. Relocated the headlight wire from the drivers side socket to the relay for the turn on. On my elky, I also replaced the ground wires to the headlights with 10 gauge wire. Now, if anything there is more volts going to the headlights than the volt gauge, with the car running it shows 14.1 volts. It is very BRIGHT
On dims it is brighter than when I switch to Brights (as the brights do not use the relay and I didn't swap the inner headlights to the silverstars) I would try it on the GN too, but for .5 volts, I'm not going to mess with it.
For the price of the pre-made harness, you can make your own and purchase the low & high beam silverstars to go with it!