FYI - How I checked ALL the inputs to the Idle Control Unit located under the passenger foot well...

The various inputs to this little black box run ALL over the place! In one case there is one signal running from the CIS-E directly to the ICU and nowhere else, so you need to monitor that input at the foot well area on my car as the CIS-E is also located in that area (to the right).

But there is NOWHERE to clamp on test wires! So I had an extra ICU I found at a junk yard, removed the cover, then soldered on wires to every single connection from the inside of the ICU. Then taped each wire to a wooden ruler so they would not short. And taped a wire number on each one - backside of tape said what the signal was and what value it should be.

Then unplugged my ICU and plugged in the test ICU - Read the various inputs with a multi-meter and watched the values as the car warmed up - all to spec. (Measured ICV with amp meter and multimeter @ ICV.)

Here are the various ICU inputs/outputs for my car...

Pin#, AKA, Signal, Range
1. [V] Speedometer signal - Not moving 0 V. > 1 volt AC @ 40 km/h
2. [TF] TF - Temperature Signal from CIS-E: 3 - 5 volts DC with engine idling. Cold Start. **See below
3. [KL] A/C Compressor: 11 - 14 volts DC with compressor on.
4. [LL] Idle Switch Throttle: < 1 ohm foot off accelerator / Open when accelerator depressed.
5. ------------------- Not Used.
6. [87A] OUTPUT (and 7) Idle Speed Air Valve: 3.5 - 5.5 ohms disconnected and ignition off...
7. [87B] OUTPUT (and 6) ...700 to 1000 mA connected at idle.
8. ------------------- Not Used.
9. [15] Positive Voltage from OVP: 11 - 14 volts DC with ignition on.
10. [TD] EZL TN (RPM) signal: Should be feedback as to how fast engine going. Same as Tachometer.
11. [31] Ground.
12. [50] Starter Lockout transmission: 11 - 14 volts DC in park.

Note: I am not clear as to WHAT each input should do to the idle? Maintain the idle, reduce the idle, or increase the idle? For example if there is a large electrical load on the electrical system (every accessory electrical gizmo on - lights on - sitting at traffic light, etc.), and the voltage drops down, will the ICU increase idle to generate more electricity or not? Maybe not that smart?