The blower motor working on full speed only is definitely the resistor, but that would not cause your P1489 and P1490 codes. Those are for the high/low speed fan relays for the engine fans. Check the fuses and relays first to make sure they are ok. If you unplugged any of them with the key on this code would set as well.
I pulled the relay and the one good fan quit.. i put working relay in place of other and other fan did not turn on. Basically both relays appear to work. I just hope if it is the fan that it's very easy to replace.
On 1998 through at least part of '01 with 3.2/3.5 engines, and for all years 2.7 engines, the windings of both fan motors are hardwired in parallell after the fuses and relays - so if either fan is running, the relays are good by definition. Same with fuses - if any of the fan fuses blow, both fans would quit. (The '01 and up 3.2/3.5's are wired differently - everything I just said does not apply to them.)
Problem has to be in the fan motor or in the wire or a connector to that fan. I forget how many connectors are on the fan assembly - certainly one going in and maybe an intermediate one, and maybe one at each motor - I forget. De-mate and re-mate any connectors in the fan assembly - more than one person has reported that apparently a connector was not fully mated or one of its terminals was otherwise not making good contact, and re-mating the connector fixed it.
And as had been said, could be the fan motor itself.
I'm not sure the aftermarket has that sensor, but IMO, any critical part that requires some kind of calibration or accruacy should be OEM only (aftermarket generally fails big time for those kinds of things). The evap. temp. sensor is definitely in that category.
Chrysler P/N 4734726 - $31 list, $21 from on-line discount dealers.
There is an access cover to be able to R&R the sensor. See the FSM for how to do it.