I recently installed some accessory gauges to my 91 240 meaning I took the center console apart. Now when I go around corners (to the left) with the heater on, it makes a squealing noise like the blower fan is rubbing against something. Is it likely that I unattached someting in the dash to mess up the alignment of the heater fan? Or is there a more likely cause of the noise?

#1 Turn up radio. If still can be heard, get big amp and speakers.
#2 Did you take turbines off shafts? Or screws from motor?
Most stuff goes back the same and should clear. Surprised there is a problem. The shame is it's a pain to get at. The 240 heater has to be the best,
but hard to get at. Mine makes noise and I have two spare motors, but can't get
psyched to do it. Less noise now, plus my 242 GLT is 20 years old and has 610,000 km. I am looking for another car, so I live with it. Yours sounds like it got shifted or there was a bit of play before. Try running the fan and with the facia pieces on the console sides off. Then, pus on the side housing pieces around the fans. See which fan blade is hitting. Also, look at the halves of the housing. Are they seated into each other properly?
Another possibility is the damper on each side that control the air direction
inside. If when fitting halves together, it was not in it is close to the blade and may hit.
I will assume it is not leaves or something else that may have fallen it.
Hope this is some help, and at least will cut down the possibilities. Let me know how it goes.
I'm just another shade tree mechanic, but have worked on just about everything.
I had a 59' Triumph along time ago in the 60's, so I had to learn.

Good Luck!
Bob

Thanks for your response. I should be headed in the right direction now.