Why would a 2000 Chevy venture air conditioning only works on high speed?

Answer 1

I spoke with a service technician because this happened on my 2002 Pontiac Grand AM GT. He said he has only seen this happen in trucks and the usual cause in the truck is the AC CONNECTION the wires themselves from the switch to the blowers. I spoke with another technician who said she was fairly certain the pontiac's problem was a resistor which powers each individual blower. I also spoke with people at AutoZone, not that they really know anything, but they thought it was the AC switch itself. I actually trust the technician who told me it was the resistor because my AC works on 4 and 5 but not 1-3 and it makes sense to me that the resistor supplies the power to each blower speed. There is also a relay switch involved in your AC unit so you may check that out.