Sounds like the fan switch. What happens if you wiggle the switch when it's on high?
Al
I noted a similar problem with my 94 Jimmy. With the fan switch in high, no fan. The relay on the firewall is/was the problem -- I tapped it and the fan came on high. Relays are cheap and easy to replace -- might want to explore that before going to the expensive stuff.
JJC
If I remember corecctly the resistor pack is for loW sppeds. The resistors are in sseries. The high speed should be connected directly to the battery most likely though a relay to the battery. This keeps the igintion switch current down to safe levels. The blower on High darws lots of current check all the connections to the relay. Joe
MotorsForum website is not affiliated with any of the manufacturers or service providers discussed here. All logos and trade names are the property of their respective owners.