Hello All. I'll get right to it. We bought a 300K + mileage 300SD. Converted to run on Veggie. The A/C compressor belt was not on the pulley. Previous owner says that the compressor seized and threw the belt. I took off the compressor and will get a new one through Advance Auto, along with the dryer and expansion valve. Before spending on those things, I decided to make sure that the blower and switches work. The fuses look ok. There is power to the fuse panel. With the key on, the buttons for the A/C generate a 'thump' sound under the dash on the passenger side. No blower though. I took off the carpeted panel on the passenger side under the dash. There is a black plastic box with maybe 10 pins to the left of the blower. I removed the connector. One of the male pins (on the box) was very loose and the receiver slot for that pin on the connector is corroded. My thought is that this might be an A/C controller??? Next, I disconnected the 2 pin plug for the blower itself. I connected a hot and ground lead to the two male pins of the blower plug. The blower works. I also removed the switch panel behind the wood faceplate. There is power to some of the wires, but there are way too many wires for me to decipher what is what. So here we are. Did my diagnostic efforts tell anyone where my problem might be? Thanks a million in advance for guidance.