That funny. I am looking at the wiring diagram and it has terminal 15X at the ignition switch (in run) and the wire is Red with a Yellow stripe and it goes fron there to Fuse #8 which is listed as 16 amps and from the fuse box to the Heater and Air Conditioning.

That means if you remove Fuse #8 and put the ignition switch in run one side of the where the fuse connects should get Voltage. The other side of the fuse conector represents the wires going to the AC and heater controls.

Replace the Fuse.
The that goes from the fues box to the AC/Heater is color is BK/CN/PK I think what llooks like CN is actually Gn for green but I am not sure. Anyway you might be able to see enough of the wire at the Fuse Box to determine the color.

If you acces the connector in the AC/Heater control you should see that same color of wire at tne Connector. In Run you should get Voltage at the Connector for that coloed wire.

Terminals on the Blower AC/Heater switch, 6 Gr/Yl/BK Goes to the Blower Motor and one the Resistor but the blower motor wire turns red before it gets to the resistor and the resistor wire turns to green, 4 goes to the resistor starts off green yellow but turns to gray, and 2 goes to the resistor the wire starts off ad Gn/RO and I don't know what RO is however it turns into yellow.

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84 300D, 82 Volvo 244Gl Diesel