My 2005 jeep heater/ ac blower only runs one speed (high) I pulled it apart and got continuity thu all four spade connection on the back of the switch ,so I pulled the blower cage down and found only 2 wires.Is there another connection under the dash that I'm not seeing? what else could caused the other speeds to stop working?

SOURCE: Heat/AC Blower fan speed only works on High

Alot of people have the same problem with the fan switch and blown bulbs. There really is no fix for this. Jeep really screwed up when designing the heater control assembly. The cheapest solution is to buy another unit off Ebay. Can always go to the dealer but be ready to PAY for there mistakes.

SOURCE: Heat/AC Blower fan speed only works on High

hello, this sounds like a bad blower motor resistor!! its cheap and easy to change..if you need more info on locations let me know,, good luck.....marty

SOURCE: 2005 jeep cherokee dash board light behind blower

Hi, you have to remove the ash tray and the panel around the radio then you will be able to remove the aircon control panel.

SOURCE: 2005 jeep laredo-heater/ac fan speed control only works on high

Hey! Oddly enough, mine started with the same thing this morning. I Googled the heck out of this and I'm more than satisfied that the most likely culprit is the blower resistor. This is EXCELLENT how-to guide (with lots of positive results): http://bvensko.blogspot.com/2008/02/how-to-repair-jeep-grand-cherokee.html

SOURCE: 2001 Jeep Wrangler heater blower stopped working

Yes I would go with the switch, BUT, does it have a resistor bank? That is, how does it reduce the speed? Many systems use resistors to lower the speed. Burnt or bad connections can cause this as well.
You can test the blower motor by connecting direct power from a source like the cigarette lighter if you are handy.
Most of the time the lower speeds konk out but the high speed continues to work this is the resistor bank that goes out.