That looks about where it was on my 91.  It's still fairly close to the left speaker, right?

That location is just about centered below the steering column.

I think it would be great for those that have it near the speaker could post up a pic. I know it gets asked often, and once you know where it is it's easy to get at, but that first time finding it ...

I just adjusted my valve clearance and have the exact same problem.  Once the engine is warm the idle drops down to 0 (well, it reads 0 on the RPM meter).  If I turn the heater fan on one notch the idle jumps up to where it should be.  Turn the fan off and it drops back down to 0. 

Did you find a solution to this problem or anything I can try?  Or should I just turn the idle up?

(On a side note about a year ago I adjusted my idle from 2000 back to 800 [to spec] without learning the cause of the high idle.  If the excessive valve clearance caused the high idle and I adjusted it down, then perhaps fixing the valves caused it to drop too low?)

Did you find a solution to this problem or anything I can try?  Or should I just turn the idle up?

Well, I tuned the idle back up to spec with the idle adjust screw. It idles at 800 rpm now, but there is still a jump in the idle when I turn on the fan or lights.  This is worrisome to say the least. 

 There's supposed to be a jump in the idle when you turn something on. There's a sensor hooked up to a throttle solenoid that speeds up the engine so the alternator puts out more when it detects a load being placed on it.

 Dave

There's supposed to be a jump in the idle when you turn something on. There's a sensor hooked up to a throttle solenoid that speeds up the engine so the alternator puts out more when it detects a load being placed on it.

 Dave

 

Okay, but only when that idle increase takes place does the idle become erratic.  Normal idle is fine, idle with lights or heater fan jumps from 800-1400 and back down again.   

Maybe that throttle solenoid is failing?

 Could be, or the connector to it is corroded. Right now I've got just the opposite going on, no load it doesn't want to idle at all, put a load on it and it idles around 800rpm.

Dave

There's supposed to be a jump in the idle when you turn something on. There's a sensor hooked up to a throttle solenoid that speeds up the engine so the alternator puts out more when it detects a load being placed on it.

 Dave

The 89 might be different but the later models just monitor the rpm and keep it constant using the Idle Speed Controller (ISC). The idle switch and vehicle speed sensor tell it when its at idle. The ECU also monitors the voltage level and adjusts the fuelling to keep it smooth.  I don't know if you can monitor the ISC pulsewidth, on later models it is brought out to the diagnostic connector. IIRC you have to tweak the adjusters so that the idle is at the correct speed when the ISC pulse duration is at 50%.

Could be, or the connector to it is corroded. Right now I've got just the opposite going on, no load it doesn't want to idle at all, put a load on it and it idles around 800rpm.

Dave

Is the idle adjust screw turned way down?  After I did my valves the idle would drop down to 0 and almost die without electrical load.