Oil light not working

I have an autometer oil and temp gauge in the car. But It would be nice to get my oil light working. It was working with the slant 6 when I pulled It this winter. Now after installing the 360... it’s not. Because I used the port on the block by the distributor, I installed it on the oil filter adapter plug. Am I not getting a ground or something with it there? How do I test it with my multimeter to find the culprit? Thanks.