Applying brakes or lights shuts down the engine

I'm in process of restoring a 77 CJ7.
Going well and runs well, until suddenly electrical problems arose. Engine starts and runs great, yet everytime I apply brakes, turn signals, headlights, heater &/or wipers it shuts down the engine. Does or would anyone have any suggestions? Thanks

 

The first place I would look is the fuse box in the firewall on the driver side. I had a 78 cj5 with a similar problem and it ended up being that fuse box had started to melt and the wires were all shorting out. If that checks out ok then check your alternator and make sure it’s charging.

 

Start with the basics as mentioned by @Squatchy as well as good clean ground wires. Something is possibly shorting and putting a load on the electrical system. Might be a good time to have the battery and alternator checked.....car parts places such as Advance or Auto zone usually offer free analysis.

 

Mine was doing the same thing, Lights, Wipers, Heater, Radio, any electronics........changed the alternator.... boom.. everything works great, no problems