Lost top speed on my cab blower motor. Speed 1 and 2 work fine, but switch to 3 and it shuts off, was working fine a few days ago. Is there a resistor or a relay I need to replace? This is my first KW, I've only been around peterbilts, but both are paccar so I thought they would be a similar set up.
Checked all fuses and swapped around the relays down by the clutch, and nothing changed.