Was in a hurry and had wallyworld do my oil and filter and now I get this.

What did they break?

https://youtube.com/shorts/EG6N81GRwRE?feature=share

It comes and goes, at full stop and on initial acceleration theres no flickering, but the antilock light is on all the time.

Reservoir is full, New drums and shoes, new brake cylinders.. new pads and rotors, original calipers.

Anyone know the location of the abs relay on a 3.1 95 century?

Need to scan the module.

Vehicle is aldl, not odb1 and I've contacted several gm dealerships in the area, no one has the scanners for a vehicle this old.

You need to call around. Someone in the area has a simple scanner that will read your OBD 1.5 system.
Here'* a better pic of the wiring.