im assuming its a vacuum leak? it only does it when i have it on the floor setting, and its really annoying. it blows on the floor, but it hisses from behind. non of the other settings do it though. i plan on taking my radio out sometime, so what should i look for to repair the leak?

 

sometimes the rubber lines in the back of the unit come loose. check there

 

I have a different problem. The bracket where the temp cable hooks to was broken off when I got the car. It is a 1987 IROC with A/C. I had to replace the heater core and thought I could repair it while I had it apart, no such luck. Tried to make a bracket to hook the cable to, no luck.
Any suggestions ????