did headlite wire upgrade. 1 problem

I did it on my car, but I dont have an info center as I have an areo. Since you dont have any bulbs hooked into the stock sockets anymore the info center thinks the bulbs are blown because there isnt any resistance.

Maybe the resistance of the two relays put together on highbeam turns the info light off?

You could either yank the bulb in the info center, or find the correct resistor to put on the old harness, or put a small bulb like a 194 on the old harness wire to create resistance. Some use the bulb method for LED lights for the same problem you have; IDK if it will create enough resistance in place of a headlight to turn your light off, but its worth a quick try.

AutoZone wiring diagrams

AutoZone wiring diagrams

For 79-88 model Mustangs
http://www.autozone.com/addVehicleId,1151803/initialAction,repairGuide/shopping/repairGuide.htm?pageId=0900c1528004e28c

For 89-93 model Mustangs
http://www.autozone.com/shopping/repairGuide.htm?pageId=0900c15280069677

For 94-98 model Mustangs
http://www.autozone.com/shopping/repairGuide.htm?pageId=0900c152801f5e3b