That would be compounding the problem even further. The parking lights and headlights are on two separate circuits. You would need a double-pole switch, and once again, the switch would have to be robust enough to carry the full current of the headlights. Even then, the OEM wiring, and the high/low beam switch built into the multifunction switch, are barely capable of carrying the headlight current safely. Offloading the full current load to dedicated wiring via a harness and relays as mentioned above would virtually eliminate the risk of damage to all the associated switches, connectors, terminals and wires in the cab, all of which are under-engineered for today's high-powered headlights.

Putting the parking lights and headlights on a single-pole switch would create an electrical nightmare, by combining the two circuits.

 

between 88 and 90, i replaced the switch and pigtail in my 88 three times, and twice in the two 89's. when the switch went in the 90, i did the relay upgrade to all 4 of them. same with the 91 and 92, the very first thing done to them was relays in the headlight system. the 91 and 92 were converted with less than 10 miles on them.
and never had a problem with headlight switches or wiring on any of those 6 trucks after doing the relay conversion.

the 88 still has the same relays i put in back in 1990

 

Does any one have a part number or good description of the harness I need to get. I'll do that relay thing because I want to put some upgraded halo lights down the road.

 

Cheapo Putco version on Amazon: . Offloads the current load safely, but the relays and wires aren't heavy-duty enough to boost the voltage and create more light output. LMC's product is comparable. RJM used to make one that actually prevented most of the voltage loss, which increases light output; alas, they're out of business. Jegs sells the more heavy-duty Painless product: http://www.jegs.com/i/Painless-Performance-Products/764/30816/10002/-1 - it's, er, spendy.