My heater quits blowing at 3000 rpm's. Checked for vacume leaks and changed heater switch. Anyone have any ideas? 1997 Ram 1500, 180,000 miles

vehicle type, year, mileage...

1997 ram 1500, 180,000 miles

Some air conditioning systems shut off the compressor at higher rpms, guess they think you need more power.

So having a look at the sensors involved with that circuit would be my first guess.

thank you

Sure, sorry I didn't have any better ideas.