67 cougar base modle ( not the xr7)

Everything time i hit the brakes or turn on the head lights, it’s kill in the motor. Is it a ground? Or why would it draw so much power that it trys to kill the motor?

Most likely your vacuum power brake booster is bad and there is a vacuum leak in your headlight door actuator system. When you step on brakes or turn on headlights you are introducing a huge vacuum leak which kills engine.

Thank you very much

These folks do a fine job rebuilding boosters for our Cougars. I have been using them for 25 years. https://www.powerbrakebooster.com/

The question is does it have a vacuum booster?

Mine does not. 4 drum brakes.

I would think he needs a vacuum gauge and start there while in the garage.

The rest of you can help him with this.

Welcome!