Chrysler Repair: blower switch 1998 Chysler Cirrus, chysler, oil light

Question
The blower switch for heat or ac only works on high #4.  I have taken apart the switch replaced and still only works on the fourth position.  

Do i just take reading on the resistors that are there?  Then can i find replacemnt ones at Radio Shack?

Thank You in advance.

Also I have a stumbling problem in gear.  Its stumbling and the oil pressure drops to the point the engine oil light comes on in gear like at stop light. I previously replaced the sending unit which was leaking before and stopped this problem for one year until now. It also seems to be overheating a little bit out of normal. Plugs, plug tower seals, valve cover gaskets, wires, pvc, air filter have all been changed.  

Thank you again in advance

Answer
Hi Dwayne,
I strongly suspect the resistors are blown and if so you may be able to get replacement...but they are very low ohmmage if they are similar to ones in the Sebring: 0.31,0.87, and 1.83 so you might need to go to an electronics supply store with a wider selection. I don't have the wattage specs. You can find the resistors just to the left of the blower motor. Please let me know if you successfully replace them; the alternative is to buy a new resistor block from the dealer.
On the stumbling at idle, my first choice would be the egr valve which may be sticking ajar rather than closing which it has to do to get a good idle mixture. So try lubricating the stem of the valve with solvent and try to move the stem back and forth with the tip of a screwdriver inserted in the slot of the stem. Other than that, a readout of fault codes might get you another clue. I believe that by '98 you had to have a code reader plugged in to get them. Let me know if you find that is not the case, and what seems to help with this, please.
Roland