Blower Motor not working on Max Speed

[jgrisi92]

Hey guys,

I've been searching for days, and whenever I google or search on the forum something along the title, I'm flooded with the exact opposite scenario, or people saying to replace the resistor pack. As far as I know, replacing the resistor pack only helps if blower motor speeds 1, 2, and 3 don't work. My 1992 240sx coupe's blower motor wont work on 4, or max speed. I've already replaced the resistor pack with a new one just for kicks and it didn't change anything (expected). Anyone else experience this problem, or can point me in the right direction?

I've found on another forum, someone stating "if its works on 1-3 but not 4 the switch controlling the relay is open. get a wire diagram and trace the a/c speed relay control circuit."

What I think that means, is the switch on the HVAC control, or speed setting 4 is not connecting correctly. Looking at the wiring diagram, it seems to take the full voltage from the blower relay, make the connection at the switch, and send it straight to the blower. I imagine my best bet is to take a look at the contacts within the fan switch on the HVAC control?

Any help is greatly appreciated, thanks!

[mr.nismo.]

Speed four is full power to the fan, your HVAC control unit needs to be replaced


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[jgrisi92]

dev71893 thank you for the reply. I investigated the switch last night and found the switch was damaged. Thanks!