A friend is looking at selling his 2004 dodge ram 1500 but he has a few issue that need to be addressed before he can do that. One of the issues is the odometer no longer displaying on the cluster and the other issue is an inoperative blower motor.
I was unable to find any relevant repair videos or process on the internet so we are going to wing it when it comes to this repair. I am not an electrical engineer and may refer to components incorrectly and may not repair thing to standard of some people or manufactures. The goal in the end is to learn and fix things if we can.
I ended up reflowing the solder on the MOSFETs and several resistors on the back of the board but those made no difference in the display operation. I ended up needing to remove the face plate and needles from the front of the board. I then plugged in the cluster and lightly pressed on the components on the front of the board. When I pressed on a group of three diodes and one resistor the LCD display lit up. This was great news and the microscope confirmed the broken solder joint. I reflowed the joints for both LCD screens and reassembled the cluster making sure to check and adjust the needle alignment.
Next up is the blower motor. A quick test at the blower motor connector proved that we had enough power to light up a brake light bulb(~3amps). I plugged in the blower motor on the back seat and it came to life. This is common when the brushes are worn in the blower motor. When the motor is shaken during removal the bushes make contact again so the blower motor will work for a time.