Front AC/Heater Fan speed resistor keeps failing every 8-9 months.

Agree with 1 resistance is also a bad connection anywhere in the circuit. Check connector's for signs of high heat ie melted conn.plastic,blackened metal terminals. Repair connector kit avail.

Thanks all! Good advice, although where can I find the specs for the Fan blower motor circuit? My repair manual only provides a wiring diagram and fuse rating. BTW, I did check wiring for evidence of over heating. All looks OK, but the failed resistor boards do show signs of overheating (excessive current draw?). Would a low voltage condition cause the problem? My alternator is orignal (156K miles), but I do not have a starting problem or low battery issue.

Check all grounds carefully & if in doubt clean/repair as necessary.Are you using an ohmmeter or just visual inspection?

I have an ohm meter, but i do not know what resistance is acceptable.

I have an ohm meter, but i do not know what resistance is acceptable.

For any ground circuit -as close to zero as possible. Also just thought of something else-- is there any damage to the heater box that would restrict or block airflow past the resistor?

No damage or blockage that I can see. I'll check the wiring when I replace the resistor board. Thanks for your help!