Went to drive my stock '89 305tpi firebird a couple of weeks ago ( I don't drive it but twice a month) and after letting it warm up a couple of minutes I put my foot on the brake and it nearly died but then the engine reved up to about 1500rpm. THen it came back down to normal. Everything seemed fine but the lights did seem to dim quite a bit when I applied the brake. Now today it started fine, took it for a drive, let it sit a couple of hours, came back out and turned the ignition to on and the lights dimmed on and off. I turned the ignition to start it and it just clicked. THen it did nothing but the lights were on and for some reason the cooling fan was running? Went to check the battery voltage looked fine. Tried to start it again and it fired right up. However, when I put the brakes on the lights really dim and the voltage goes down to about 9. And for some reason the fan is running all of the time the ignition is on. Never did before. Could I have a short somewhere? A bad battery? The alternator seems to be working.