when i run the fan setting in the vehicle, especially when the AC is on. a horrible noise is coming from the vents that sounds like a squeal. I would say its a fan, but I dont think the 740 has individual fans in each of the vents. It's especially loud on the passenger side. is this a sympton of a bad blower, or does the AC system need lubricant?

 

Sounds like a bad blower motor. That is a pretty common problem with 240 and 740.

 

Is the blower motor on a 89 740 a one or two terminal connection?