I have a 1995 Chevrolet Suburban that the a/c fan speed works on every position except high. I have replaced the resistor and the fan speed switch. Neither of those things fixed the problem. With the connector off the blower motor and a test light attached, power is present in all positions except high. When switched to the high speed position power is not present in the lead. Please advise. Thanks
From a fuzzy memory, I think that the high speed position is powered separately through a high current fuse underneath the hood and then through the blower relay.
That’s fairly common with GM vehicles.
If the fuse has gone south that could be a sign of a worn, dragging blower motor.
There is a Blower motor high relay.