I find that this seems to be a common problem and is easily solved. Replace the blower motor resistor with an after market resistor, they are larger than the OEM part and will disipate heat better. Easy to do, 6 bolts hold the under panel on the passenger side. Then against the firewall is the resistor held by 2 bolts which are 7mm. You will need a universal on an extension to remove them. Job took me about 20 minutes. Fan now works on all speeds. Cost of resistor about $18.00.