I did a search and found some good posts and a repeated history of people inquiring about the now famous "charge and brake lights on". I too have been having this happen the past two days. They are now on and staying on. I tested the voltage. It is barely charging at 12.85 volts (is this even considered charging?). This intermitant lights makes me think it is in fact the brushes and not the voltage regulator. It is my understanding that if the voltage regulator was bad it would not have been intermitant and the truck would have quickly died? I did see alot of posts for problem but I did not see a result post saying what fixed the problem. I ordered the brushes from toyota for 20.00 thye will be here tommorrow. My question is: was the communicator metal changed in the mid eighties thus effecting the ability to change brushes and have them effectively carry the charge across the worn inferior metal. Has anyone had experinece with the year of the alternator effecting the replacment of the brushes due to lesser quality communicator surface?
For those of you who might not have run into this yet, I would get familiar with it. It seems like this is a common problem. If you are running an older gen truck, possibly put some brushes in your roadside kit.

I will post my results when I get the new brushes in, as to whether or not it was that.

 

I replaced my brushes after the same symptoms and no more problem.I think your diagnosis is dead on.You'll need to be a fair solderer to make that repair.BTW mine is a 90 model.
Bigblock