all eletrical restart when I hit the brakes??

I have a 92 intergra gs-r. I have started experienceing trouble a couple of weeks ago. Whenever I hit my brakes, or turn my blinker on etc.. my eletrical system restarts. I temporarily lose all my lights and radio etc... I use to have a 91 honda accord and it did the same thing????? It doesn't happen all the time just some times. some times it wont even start. I tried to replace the main relay(someone told me thats what it was), however after a couple of days. it started again. please help!!!!!