This is a guide for repairing the Blower Motor Resistor on a Volvo 850/S70 with manual A/C. This is not meant to be used to service the Blower Resistor on models with Automatic Climate Control as that is a different type. A new Blower Resistor for these cars can run upwards of $75 to $95 plus shipping depending on where you buy it. By following the Procedure below you can repair your existing Resistor for as little as $2 if you already have the Solder and Tools.

Many questions have been asked about the air conditioning system used in the 1993 and on Volvo. 1993 was the first year for the North American 850, as well as a change in refrigerant from R-12 to R-134a. The change was mandated by the Federal Government. When the refrigerant change occurred basic operation of the A/C system changed as well from a TXV (thermal expansion valve) to a CCOT (cycling clutch orifice tube). Below is a basic block diagram of the components, followed by a brief explanation of their operation.

If you have coolant leaking on the drivers side floor of your S-80 and you think the heater core is at fault, most of the time it's just the o-rings on the end of the pipes going into the heater core that are at fault. This will shine a little light on the process of replacing those o-rings. Start by removing your lower dash trim 2-25torx screws and the lower console trim. This picture shows the fastner on the console trim, rotate it so it's straight up and down, pull it away from the console (at the fastner is) then slide the trim towards the rear of the car releasing it from the console.