Car looses power when the breaks are applied

Does it do this with the vehicle stationary (sitting in park and hitting brake pedal) or with vehicle moving and braking? If the latter, may want to investigate battery connections and battery cables, momentum from braking may be causing a connection to stretch causing loss of electrical power in vehicle. Check not only main cables but smaller ground wires. If it happens when stationary the only thing electrical on a brake pedal is the brake pedal position switch, you'll need a wiring diagram to trace out that circuit, I can't imagine a scenario where that circuit could cause symptoms like yours but who knows, given how complex harnesses have gotten over the years.

PS: it's also possible to have a bad terminal inside a battery, grab hold of either terminal and see if it moves or feels loose. A sure way to test is switch out battery and see if problem persists.

Thank you for your input. It only happens when the car is in motion. I’ve quit driving it since the last occurrence. I was coming down a hill and the car completely quit.

Okay well that's actually a good thing, because it really implies the problem is a loose electrical connection. The engine will quit when electrical power is lost. All your described symptoms sound like lost electrical power. Again, check the battery itself, then all cable connections to battery. If you lack a meter, just turn on engine in driveway and with it running, carefully take hold of a battery post and wiggle it around. It should not be loose. Also take hold of cables, one by one, and wiggle them around, look for a bad, loose, or frayed connection. If at any time engine wavers or lights dim you will have found your weak connection. If you can't find anything wrong, then problem may be internal to the battery - a bad internal post connection, a dead or shorted cell, there are metal plates in a battery and one may be loose and moving when you stop and create forward momentum. A good load check on the battery might also be in order.

PS: should mention, never short between the two battery posts, you'll kill the battery and may blow a fusible link.

My car when headlights are on at a red light in a minute or two lights will flicker then lose all power engine dies. But if i let off breaks at that moment the car will stay running but as soon as i step on breaks it will die