Failure in the blower motor power module (automatic temperature controls) or resistor block (manual AC) may cause the heater blower motor to work only on the high setting. The connector to the power module/resistor block is known to overheat (and sometimes melt). The connector or terminals should be replaced; a replacement connector is available.Google+
Car Problem Reports
Jeep Grand Cherokee AC Blower May Only Work on High or Melt Connector at Blower
Jeep Grand Cherokee Problem
Average Mileage: 166,531 mi (48,000 mi - 1,200,000 mi)
My experience with the ac blower connector melting is one of the flaws in that year of jeep. I simply cut that connector out and put a connector from Dorman® Tech Choice™ - Blower Motor Resistor Connector Part # 973-304 $9.99 can be purchased from Orielly auto parts or online at Dorman.com.. Replaced that connector and I have (NOT)had that problem again. One of many poor designs flaws from Chrysler.
Visitor, 2003 Jeep Grand Cherokee, 160,000 mi
2nd time this module melted.
Visitor, 2002 Jeep Grand Cherokee, 120,000 mi
Wires at the heater blower resister burnt and melted the resister. Had to replace wiring and resister
Visitor, 2001 Jeep Grand Cherokee, 124,000 mi
Blower controls would randomly turn on / off. Wire was melted near the resistor. Replacement took place on 02/2011 and cost $190.00
Visitor, 2004 Jeep Grand Cherokee, 102,000 mi
ac/heat only blows out on high, there are no mid-level blow levels
Visitor, 2003 Jeep Grand Cherokee, 67,000 mi
First the AC would stop blowing out the dash vents when I accelerated redirecting the air to the defrost or floor vents. Dealership told me it was a redirection of power when I accelerated. Didn't sound right but I went with it. A few years later cruise control doesn't work, heater and AC both do not blow out the dash vents only defrost and sometimes floor vents. On top of that if it runs too long I start to smell a burning electrical smell. Thanks to this site I think I know what needs to be fixed with out spending a lot to have it looked at.
Visitor, 1993 Jeep Grand Cherokee, 160,000 mi
wiring or connectors not melted, but the resistor went bad and before replacing i went through many relays and switches. overheating was the problem, but luckily it never melted
Visitor, 2004 Jeep Grand Cherokee, 131,128 mi
no blower motor at any speed resistor plug melted into case bought new cable for blower motor and resistor and purchased a new resistor
Visitor, 2004 Jeep Grand Cherokee, 107,500 mi
Heat and AC only blow on HI setting.
Visitor, 2000 Jeep Grand Cherokee, 100,000 mi
I just needed another connector installed and made the mistake of taking my 2000 jeep to Suncost Chysler in St. petersburg FL. After they were done with my car it cost over $1800.00 as they broke my vent doors after replacing not only the connector but the resistor. It now required removal of the dash to fix vent doors. All these systems worked fine when brought into Suncost. After they removed the dash they claimed the condenser was leaking freon. This car could freeze your legs before they got ahold of it.