Just a quick guess I have would be the high beam switch. I would think the blinker/high beam lever in the forward position is not making a good connection. The terminals are burnt out. When you pull it back the terminals are making a good connection hence the high beams work. I had to replace my blinker/high beam lever and it is not a very hard job. It just takes a little bit of time. Hope this helps.
'94 AA Yellow