I have a 1999 Jeep Wrangler Sahara 4.0L and while driving I can hear a faint humming every so often. I thought it might of been the A/C motor, but it was still doing it with the A/C turned off. It's hard to say which side of the engine it is coming from, but I would say the front passenger side.

SOURCE: 1999 Jeep wrangler gets water in the passenger floor when the air conditioner is bring used.

My wrangler was doing the same thing. As it turns out the condensate dripping from the drain tube was running back toward the firewall along the bottom of the tube and was getting past the foam gasket which wasn't sealing off very good any more because of age, dry rot or for whatever reason. The solution: Go to the parts house and get a bypass hose, which is a piece of heater hose molded in a 90 degree bend. They will have one that fits snug over your drain tube. You could even put a bit of black permatex inside the hose to help seal but I didn't need any. Now the water drips out below the hole cut into the firewall preventing the liquid from getting into the cabin of your jeep.

Good luck!

SOURCE: 2007 jeep wrangler sahara with a mopar remote starter just beeps

That's not a remote starter on your key chain, it's a keyless entry for an alarm system.

SOURCE: Washer fluid will not spray in 1999 Jeep Cherokee sport

If there is a hum when you press the washer button but no fluid than try cleaning the holes where the fluid comes out if that don't work than try replacing the supply hoses. If there is no hum than first check the fuses and if they arn't blown than you more than likly have a faulty motor. Both? unlikely but not impossible. Good luck.

SOURCE: 1995 Jeep Wrangler 2.5L Fuel Pump/Check engine light

Could be one of several items...I'd check the fuel pump relay, auto shutdown relay and the ignition switch itself. I'd bet on it being one of those relays but, we all have been fooled at least once!!! I'd also make sure that body and engine grounding is good and clean. Relays can't work properly without a good ground.

SOURCE: how to replace window regulator on 1999 jeep grand

sorry I don't have much on this one. But, once the door panel is removed, you need to disconnect the glass from the regulator. I can't remember... but I think it is held on with U clips. They are just pushed in on the back side of the trolly. Too release them just push to one side. (see pic)
*****NOTE: this is from another vehicle but the pin is the same...in the pic. the pin is being pushed back into place.

push the glass all the way to the top of the door and tape it there. Unplug the motor, unbolt the regulator and remove.

(Im pretty sure that year had 2 pins to hold in the door glass, if I'm wrong you will clearly see 2 X 10mm bolts holding the glass to the regulator)
hope this helps.