https://www.ford-trucks.com/article/...r_IAC_Fix.html

I'm researching now for Aerostar IAC resistance measurements.

 

wouldn't the values be the same if not similar? I mean from the explorer to the aero's IAC resistance values.

 

If you unplug the IAC and measure the resistance between the two termilals, it should read between 6 and 13 ohms in one direction, but the other direction might read lower because there is a diode. Depending on what kind of voltage your meter applies, you may or may not detect the presence of the diode, and the resistance would read almost the same both ways.

 

with IAC problems, always check for diode failure in the IAC with a meter that has a diode check ohm meter function.

Always replace if diode is failed, either shorted or open, there is no protection of the IAC circuit in the PCM/ECU when the diode is open and the solenoid will not open when the diode is shorted. the diode will usually fail as a short (low resistance <5 ohms) but can also fail open.

the diode is in parallel with the IAC coil and is an EMF surge protection device that protects the output of the PCM/ECU from a coil kickback voltage on turnon/off.
using an ohm meter that applies less than 0.5v dc, the diode will not be turned on in the forward bias mode, + lead to anode. meter will only show the resistance of the solenoid coil with leads in either position 6 to 13 ohms unless the diode is shorted then will show less than 5 ohms in either direction.

using an ohm meter that applies greater than 0.6 v dc, the diode will show less than 5 ohms with probes connected , when + lead of meter is connected to lead to anode of diode, diode forward biased.
resistance reading with probes reversed will be greater than 6 ohms <13 ohms, diode is reversed biased and turned off.
Meter range switch will be marked with a diode symbol, arrow pointing at flat bar for diode measuring range or will be indicated in instructions.