Hello. I know that with my 69 I replaced the pull on/off switch. First time I tried them the Low beams worked but when I tried the high beams they worked for seconds and then started to strobe. Tried them again after that and only lows, nothing from the highs. It turned out that the switch has an internal circuit breaker and some of the replacement switches weren't of decent quality and can't handle the wattage of the highs. Wondering if you have replaced your switch or perhaps it just quit working when it comes to the high beams. Good luck.