I have an odd problem. The interior blower motor for the A/C - Vent stops from time to time. It works for awhile, then after the car is shut down for awhile and then started later, it simply won't work. If put on vent allowing exterior air to blow in while driving on the freeway, it'll start working again. It'll last for a few days, then will simply not start again. My car has sat all day, then when started, the blower won't work until, once again, I get out on the freeway allowing air to blow in from the outside, it'll start blowing. Any recommendations or ideas? Thanks.

 

What year Tucson? I have a 2006 Tucson and I had the same problem with mine. The fan would blow and then just shut off for no reason and a few seconds later kick back on. It wasn't the relay because I could hear it kick on and off. The problem is the fan speed dial itself. Actually, the whole HVAC control panel. All 3 dials are combined in one control unit. I purchased a used one off eBay for about $20 and replaced it myself. It solved the problem completely and it hasn't come back in over 2 years.

If your car is still under the 5y/60k mile warranty, go back to the dealer and tell them to replace the HVAC control panel. Otherwise, search eBay for good used ones.

The "Heater Control Unit" in the picture below:

 

Same issue with my wife's 2005. I haven't looked for the relay yet, but where is it and is it worth replacing it first just in case?