My blower only works 1 through 4 and will not work on the highest position number 5

{: ) Check out the J-case fuse (square) labeled BLWR 40amps at the underhood fuseblock. This fuse is the source of power to the blower motor when position 5(max speed) is selected. If this fuse is tested to be okay, you need to access for the blower resistor connectors. Turn ignition on, and set blower to max speed (#5). Probe on the blower resistor terminal (orange wire) and you should get 12volts, also probe the terminal (red wire) which came from the 40amp fuse. 12v should be present on these two terminals at the blower resistor when at max blower speed. Particularly on the orange wire, if you don't get 12volts when at #5 position, it 's probable that the blower speed control switch is faulty. But if you did got 12volts during the procedure, then you should replace the blower motor resistor. Goodluck.