Charger light dim, won't power on normally.

I have 2 different MacBook Pros. Both of them are the exact same year/model--2009 2.26Ghz 13". Each MacBook Pro is experiencing a rather odd set of identical (to a "T") symptoms, and I'm not sure what could be causing them.

First of all, I should mention that neither MacBook appears to have suffered liquid damage. No corrosion visible, no burning, no dead keys/liquid marks, nothing.

The symptoms are:

- Charging light dim green. I made sure the top case wasn't shorting, and it wasn't. The charging light is dim even with no accessories/peripherals plugged in (fan, SD, hdd, keyboard, etc). Tried multiple chargers.

- Won't power on normally; must do the "emergency boot" (I'm not sure of the exact name for this boot process), in which I hold the power button for 10 seconds without charger attached, then attach charger while continuing to hold power for 10 more seconds, then immediately pressing power once. When powered on this way, they both work perfectly fine! (Except for the following other symptoms)/

- Keyboard backlight does not work on either machine (I made sure the cables were secure). The keyboard backlight buttons on the keyboard function once the computers are turned on, and it shows the backlight being raised/lowered, but it doesn't actually work.

- The sleep light on each machine does not work. I've tested each hard drive/light indicator cable/assembly in other MBPs and they work fine.

I've tried the normal course of resets--PRAM, PMU, etc. Nothing has any effect. The computers simply won't power on normally, but will power on just fine when booted using the "emergency boot" process. I know this method bypasses all on-board sensors, so that makes me wonder if some particular sensor (temperature?) is bad or damaged.

Any idea what to check or try? Any help would be greatly appreciated. I have 2 perfect-condition MBPs that are currently only good as paper weights. Would love to get these guys up and running.

Thanks in advance!