1999 S-10 Dash heating up ?

I just went over 100k and the dash seems to be heating up badly, the entire instrument panel, A/C , heater area, Radio, even the speedo and Rpm gauge, also there is hot air coming out of the vents. There is no condensation so I would assume its not the heater core. Also I have an exhaust leak, possibly the manifold.

Does anyone have any ideas befor I rip the dash apart ?

Any thoughts would be helpful

Thank you

I would check for good vacuum from engine to ac/heater controls.
Also vacuum tanks and lines for leaks.
Auto matic or manual ac/heater controls?

Do you mean that there seems to be a heat buildup behind the dash from the vehicle's normal heater system? If so, I would look for a disconnected duct/hose. I have never torn apart the dash, but I would assume there are hose assemblies there to duct the heat from the core to the dash vents and the defroster. perhaps one (most probably the defroster) has come loose. Does the airflow change according to switch position?

the mode(floor, defrost and so on) on my 98 ext cab LS seems to be vacuum controlled, but the temp selector is actuator controlled. an answer to peterjon's question about air temp when knob set to cold would help pinpoint this a bit. knowing the motor size would help. if it is a 2.2 like mine, there could be a leak at the manifold. seen lots of them where they would crack just above the flange(like mine is). also the flex coupling there has disintegrated in mine, and all kinds of hot exhaust has blown onto my driver side upper control arm bushings causing a big camber problem. been a month since you started thread, hope you found problem without too much trouble, or decided to let it go for winter....let us know.