I Have a 1999 ram 2500 4x4 (Heavy Duty version) with the sport package, and the quad head lights. My issue is with the passenger (right) side , quad high beam not coming on when the high beams are selected. All of the other 3 lights do come on when the high beams are selected but not the right side one. Now I have replaced the quad light relay , and change the bulb, and no difference. However I did check for 12 volts are the headlight plug and I am only getting 10 volts. Does anyone have any suggestions!
Also my fog lights do not come on as well.

 

If "quad high beam" is your term for the inboard light, both inboard lights are simply wired in parallel. If one works and the other doesn't see enough voltage it's a wiring issue. There is a splice (S181) that carries 12V from the fuse box to the lights. There is another splice (S144) that connects the wires going to the relay. Just trace the wires from the right headlight und you'll probably find an issue with one of the splices. Supposedly the splices are under/along the radiator support.