Okay so here is my issue, when i start driving my 00 cherokee every so often ill get a loud whistle whining noise. It sounds like its inside the dash but the other day when i popped the hood i heard it even louder in the engine bay. I also noticed that im having another issue where my heater controls only work really when on 4. 1-3 dont really do much of anything. I popped apart the dash and checked the vaccums behind the controls are fine and the colored tubes going to the plug behind glove box is fine. Could they e popped off somewhere else? Where do i look. Where do i start? Sound like somethin in engine bay is popped? Jeep seems to idle a little rough too

 

Get a can of carb cleaner and go spray the whole engine bay (systematically).
When idle changes momentarily, you have localised the (or a) vacuum leak.

 

Ill do that defintly, any idea why heater controls and whistling happening?

 

Controls are vacuum operated IIRC, whistling could be the 'false' air being sucked in.
Blower motor is on the list.

 

Start by inspecting the rubber vacuum tube fittings on the intake manifold to make sure they're all connected. If they're okay, inspect the entire length of the gray vacuum tubes from the intake all the way over to the cruise control servo and make sure the tubing is not broken or a hole chafed through. Make sure the 3 mm tube that tee's off the larger vacuum tube (near the evap duty cylce solenoid) and goes to a check valve before it enters the firewall is secure.

The vacuum tube continues past the cruise control servo and goes to a vacuum reservoir behind the right front bumper end cap. Occasionally the tube will break or chafe through behind the battery.

You can view the vacuum tube connection at the vacuum resrvoir by laying on your back with your head under the right front bumper end cap, pull the right wheel well liner back enough to look up and, using a flashlight, look to see if the reservoir tube connection has come loose.

 

This, more than likely, is the blower motor resistor block burned out and needs to be replaced.

 

The loud whistle sounds like a vacuum leak. But the heater controls sound like a different issue. When you say 1-3 don't do anything and only 4 works, are you refering to the fan speed? That is likely a blower motor resistor.

 

I looked under the headlight to thay resevoir and has not come loose. If i spray carb cleaner on these vaccum connections while running will the idle change when i find the leak? And what bout these heater
Controls

 

Yes 1-3 dont do anythingfor blowing speed. Than when its on 4 it pushes full speed

 

See post #6.

 

Yes.

 

I don't recommend duesching down the engine bay with carb cleaner. There's too many plastic and rubber items (let alone painted items) in the engine bay that will be affected by it. If anything, use an unlit Propane tourch to probe around with.

If it's whistling that loud it's a pretty good leak. Do the visual inspections I outlined in post #5 before using a fire starter to look for the leak.

 

Off topic because his doesn't have one but have you ever gotten propane a little to close to a distributor while checking for leaks? It can be exciting.

 

I imagine so!

But who would be checking for vacuum leaks around the distributor. LOL

 

Seriously, we can argue about everything here. I'm not talking about doushing down the engine bay. I'm talking about little sprays of fine carb cleaner mist.....jeez. Many have tried this, please. I assume some common since here CC.