This is an easy fix. Remove the pannle under the steering wheel. You will be able to see the body control module. There are 5 connectors on front of the bcm you will be working with the gray connector. If you look close at the connector you wil see the holes in it are numbered and lettered. You need to find B1 black wire with white stripe and A5 dark green with white stripe. Strip back both wires about 1/2 inch and solder a diode between the two. I use radioshack part #276-1661. Before you solder the wires turn on the high beams and see if the fog lights come on. If the dont reverse the diode between the two wires and try the high beams again. The diode is kind of an elestrical check valve,only lets power go one way. This will also work to make the low beams come on with the high beams. Put a diode between B1 black with white stripe and A4 black with white stripe(low beam control). Check the install the same as with the fod lights. If the low beams dont come on reverse the diode.
01 1/2 ton suburban, 6.0L, MTI stelth 2 cam, MTI 2.055/1.60 heads, GMS Maf, 3200 yank, Dynatech headers, King cobra air intake, 42# marine injectors, 05 electric fans, ls1 edit, fourth set of 4.56 gears. Fast for a led sled.