98 S10 4th fan speed won't work. Please help

I have a 98 S10 with the 2.2L. The fourth fan speed does not work. I have replace the AC relay, the blower motor, the voltage regulator under the hood, and the fan switch itself and still no high speed. I am at the end of my rope, and completely drove crazy trying to fix this. If anybody has any more suggestions please help.

I have a 98 S10 with the 2.2L. The fourth fan speed does not work. I have replace the AC relay, the blower motor, the voltage regulator under the hood, and the fan switch itself and still no high speed. I am at the end of my rope, and completely drove crazy trying to fix this. If anybody has any more suggestions please help.


Welcome to AF

The lose of only one lower speed on blower motor is usually the blower motor resistor block or wiring.
Is this a 5 speed fan setup?
What regulator underhood did you replace.
Was it the resistor block?

High speed is the only speed that does not run through the blower resistor. At the connector for the high blower relay: Check for battery voltage at all times on one of the orange wires. (30 amp HVAC fuse in the underhood fuse panel.) The other orange wire only has battery voltage when the blower switch is in the HIGH position with the key in the RUN position. Also check the black wire for ground. Speeds 1, 2, and 3 are working which means everything else in the blower circuit is operating corectly.

It's a four speed fan, and I changed the resistor.