So my  88GL heater fan is only blowing with speeds 1-3.  To get speed 4 to work I have to press down on the knob.  I don't think it is a relay issue, just the knob/unit on the dash is worn out and needs replacing.    So how can I replace the control knob/unit on the dashboard without tearing up the whole dash?

 

 

I'm thinking if I pop off the square access port next to the knob unit, I can then pull out the unit through the square hole. (if it is indeed a square hole behind the cover plate)   Any ideas?  Anyone done this before?

It won't fit through the small hole. The section with the fan switch and buttons comes off without removing the entire dash.

 

If no one else replies before tonight, I can look at more specifically how to get the piece it mounts in off. It might be the trim piece around the top section and instruments.

you gotta carefully pull off the selection buttons. The AC and HEAT and BI-LEVEL and defrost buttons all pull straight out. Just be careful not to break them. The easiest way I think to do it is to pull off the 1-4 fan speed switch first, and then work your way up, Behind some of those selection buttons are screws that hold it all together / in. I don't remember which ones specifically, but they're there.