Ok, so today I sat while on the phone and let my brick warm up. It's a 90 740T.
The AC was on because it had been parked in the sun (we in california think it's better to build wide parking lots rather than compress a lot into a garage and save any space. Duh.). I think the aux fan is not related to the other problems. It's possible that this is all caused by a tight P/S belt causing more pull on the car, slowing charging combined with the heat, lowering the idle. But why should the idle drop as the car gets hotter??

So, the car finished warming and continued to heat up. The temp gauge moved slightly to the right of its usual 90 degree (vertical) place. The outside temperature was about 99 when I left work.
Past warm as I got off the phone, I noticed my idle was just above the mark that appears to be at 400 rpm! I got out to tap on the IAC valve, no effect. As I reached for my throttle spool to manually rev the engine, I nearly burned myself! The entire engine bay was about 150 degrees. I figured it was just hot due to sitting so long. I checked my coolant (through the bottle) and it's halfway between max/min - perfect. The H20 pump is new, the radiator R/R'ed and new upped hose. Everything was even gently flushed with a garden hose as I don't trust any sort of chemical flush.

I drove about 3 miles, stopped, found America's tire Co. was closing in 10 minutes and wouldn't rotate my tires (I'm sick, so sue me). I drove about 7 miles and stopped at a bookstore. I debated waiting in the car and reading, then decided to check to see if my A/C aux fan was running. NOPE! it was off, didn't run and it sure was hot enough to. The A/C was also switched on. At this point, I turned off the A/C and left it off.

I do believe my P/S belt is over-tightened, but I've been sick and busy and unable to get to it for this week. It's not severely over-tighetened (no whining bearings) but I feel more drag than usual on the engine, like I've got the A/C on, even though it's normally not. The clutch is not stuck on.

I went to a meeting for relay for life and left in a hurry, then turned around and drove back up the block - I had left my keys inside. When I reached my car and started it the first time, I noticed it was still fully warmed. I don't believe the 740 compensation board is as brute force as the 240, so I think the temp was accurate.
The second time I started the car, the idle was again very low (about 500-600 rpm). It slowed to 400 and ALL of my dash lights dimly glowed! I've never heard anything about this before and it frightened me. The IAC was cleaned a few months ago when I was cleaning the EGR. I used non-chlor brake cleaner, as recommended by the mechanic I have used. Perhaps this stripped the lubricant from it or something.

I don't know what the deal is, but I'm quite worried. I've got enough problems to consider junking this old guy (232K) as it has a hood dent, mismatched door, needs new front hubs (bearings actually) and rotors (what 90 doesn't?), headliner (that's only about $50 parts and I can definitely do it), and has tail-light problems and needs a nearly unfindable EGR temp sensor.

PLEASE, help. I really don't want to buy another car. I love my Volvo!

-Will
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1990 740 Turbo, on its way to stock specs, maybe beyond