My ac quit working about the same time my abs and brake light came on. I have power to the relays and if I ground the ac relay my compressor will work. Are these 2 systems sharing a ground somewhere?

 

No, they don't (at least until you get back to the negative battery terminal or frame ground).

What relays?

Have you checked for fuses in common with both subsystems?

What does "My ac quit working" actually mean? What works or doesn't work in that subsystem? Which climate control is installed?

Details are important.... ACCURATE details more so.

 

They may not be connected just thought it strange they both quit about same time. Checked ac pressures and they are good, so started checking fuses and pressure switches and everything checks ok when I got to relay on fender well there was power there so tried grounding it, the compressor cuts in and cools fine. Not sure where to go from here. Would at least like to get ac working proper.