Rep Power: 0

I'm helping a friend with his 2002 Civic. I'm getting 7.1 volts to the ELD no voltage to the 02 heaters looks like the alternator isn't charging either. He took it to a shop to get his cooling fans working there not getting power either same with AC they hooked up the fans to the heater wire to the 02 sensor.all the fuses inside and under the hood have power.
any ideas?

 
Rep Power: 228

Does the vehicle have a code for o2 sensor or heater circuit?

If no other issues than I'd suspect the O2 needs to be replaced (if codes on). The o2 voltage is not constant on the heator, its governed by variable resistor. So you may see no voltage, if the resistance is not where it should be.