Hi, i have a 84 gl wag that did a something like this, only i lost all the lights. turned out to be a ground wire under the dash. it was black had a large brass ring lug located on a harness near the floor by the steering column left side of it. i had to take out the ecm to access and find this ground wire, once i did locate it and made it good ground all was well again. since you have the low beams this may not be your issue, but there are grounds at the back of the headlight fixture that may be, each side has a ground to body, they can look good but have rust under the bolt attachment. fairly easy to check and might be the problem. btw the headlight hi/lo & turn switch is not too hard to do, remove the steering wheel, and it is right there and slips off the shaft, it is held by 2 small screws in the bottom of the column covers under the wheel. at least this is how my tilt column style is done.