You need an ohmmeter with a good low-resistance range to measure the actual values. Those resistors have values around a few tenths of an ohm. If you are reading continuity at each end of each "coil" they are almost certainly OK. Of course if there is a burned area and the ends are just barely touching all bets are off, but you could see that easily.

The other two-lead widget is a thermal fuse which opens if the resistors get overheated (for example, if a mouse nest in the heater box catches fire. Don't ask how I know). If it's open I believe you will not get any fan including high.

My Ford dealer has them for my '84 F150, for $23. Pep Boys, etc. did not.