Car died at light, tried to start then clicking noise. car started on a jump. then replaced the battery & altenator. later on driving car again. car dies at light tried to start then clicking noise again. after changing the battery & altenator what would cause the car to die and not start would it be the solenoid on the stater???

I would check your ground from the battery to the frame/engine and also the positive battery lead where it connects to the starter/relay

Looks like it needs adaptation/relearning.

I would say change the alternator out. Start with the simplest and cheapest factor first. Without the alternator keeping the engine running its hard to put it any gear.

You got a jump and it ran fine? It's your battery. The lights and radio are much easier for a battery to handle than spinning a car engine. Again, if all you needed was a jump, you have a bad battery.

Yes... Your battery died. But why?

First, leave the cables on longer, a good 10 or 15 minutes. When you hear that clicking noise, it's because there is not enough power available to turn the starter. It means you need more power. Leave the jumper cables on for a few more minutes and you will have the power you need to start the car.

Once the car is started, remove the jumper cables and pull the positive (Red) cable off the terminal on your battery. If the car stays running, get a new battery. If the car dies immediately after pulling the positive battery cable off, then your altenator has gone out. The altenator is the electrical generator that provides electricity to your lights, engine, stereo, AC, etc. It should be putting out about 14.2 volts. Since your car is a 12 volt system, there are a couple of extra volts to spare, which are used to recharge the battery. It takes a lot of power from a battery to start the vehicle. That's why the alternator is there to takeover after startup, plus recharge your battery in the process.

It cold still be the battery if you didn't let it run at least 15 minutes between starts. The problem you get with a battery low on fluids is a dead cell situation which will give you these symptoms. Now, the problem itself actually sounds like you have a bad voltage regulator which is shorting. You can have the Alternator and voltage regulator tested, the two are built together in your model so it's a one stop test. Make sure all your battery cables are good and tight and clean, if they are corroded it will do this and it will do it if it is loose. Make sure you actually physically check the cable because if the corrosion got under the protective cover it could have caused the wires to basically break in the cable. (Doesn't happen often but it can) If the alternator checks test the battery, they can test both at Auto Zone, Advance Auto or Pep Boys so you get the part you need.

If you have a new battery and it keeps going dead, then either you have a bad battery or the alternator is not charging properly. Altenator not charging could be either a bad alternator, loose belt, or bad wiring coming from alternator.

disconnect all the connections to the battery and clean them , also clean all the grounds, check the alternator to engine ground, and engine to body grounds, what you describe is indication of a bad connection and applying the brake is enough to to lower the voltage needed to power the ignition circuit, brake light use a lot of juice

ignitor

Well odds are that your blazer is fixed by now. Either way sounds like a bad battery, that's why you need jumps all the time. Why it would die, there are too many possibilties off hand. So what was wrong with it?