Co worker is driving a 92 Leggy thats seen better days, belongs to her brother.

I try and help her out when I can, replacing the rear struts with some from the wrecking yard.

Now her heater quit working, right when temps were in the 20's.

All fuses/relays check out, no power to the blower.

I suspect the switch is bad.

Resistor pack failure? I've ran power straight to the fan for a temporary fix before.

Sorry to hear this. Heaters seem to fail when it's really cold, wipers fail in the rain, and power windows always seem to stick down in the rain   Might want to check the resistor block too just to be safe. Good Luck!

Check for 12V at the motor on both sides, and check at the Resistor block.

Could also be a dead fan switch If you have voltage on both sides of the motor and both sides of the resistor.

No V at motor at all, is the resistor pack the same as the EA's?

No voltage is gonna be a blown fuse or dead blower relay. Fan switch grounds the circuit after it goes through fuse/relay > blower > resistor. At least that's how it is on the 2nd gen legacy models. 

Is the relay part of the A/C ones in the engine bay?

No. The ones under the hood are just compressor and radiator fans.

 

Blower relay is under the dash somewhere. Maybe top left corner on the firewall?