abs light on 1995 Subaru Legacy

air conditioner or heater fan triggers abs light.
Instant power loss then abs light is triggered.
Abs light does not come on if (heater /air conditioner fan)
is not running.

Asked by for the 1995 Subaru Legacy
The system voltage needs to be above a certain level or the ABS System will turn off and the lights will come on. This may be that when you turn on the A/C the system voltage is dropping, causing the ABS system to shut down. This may not be and ABS issue but a system power issue. Check your battery, battery cables and charging system.