Heater Valve Access

My heater is not putting out the heat that I think it should in my 99 Cherokee. I'd like to access the heater control valve and make sure it's opening all the way. Would someone please describe the process or point me to the information?
Temp. gauge reads 210 and this fall I ran a can of flush through the system and changed the coolant. Before spending the money to have the system professionally flushed I need to be certain that the valve is okay.
Thanks.

I don't think that the 99 has a heater control valve, just a blend door. You might look into whether or not the blend door is functioning.

Look at the vacuum lines running along side your battery. Make sure they're not cracked. Also make sure the line us plugged into the bowl that's up under the bumper on the passenger side.

I've been doing some reading in response to the first answer. I think I have symptoms of the dreaded blending door failure. I found the Heater Treater web page and wonder if anyone here has used one. Accessing the heater box from the glove box is vastly preferable to disassembling the dash and spending 119.00 rather than hundreds is a no-brainer.

The dreaded blend door issue is more isolated to WJs, not the XJ. You could also have a plugged heater core.

Note from DJ
97 and up blend door fix and information
http://www.naxja.org/forum/showthread.php?t=1014264
OP by gba88
Hi Guys, I finally fixed the heater blend door in the 99 I've been working on.

djgrayxj said:

Note from DJ
97 and up blend door fix and information
http://www.naxja.org/forum/showthread.php?t=1014264
OP by gba88
Hi Guys, I finally fixed the heater blend door in the 99 I've been working on.

Click to expand...

Oh boy, another job in a tight space with sharp edges all around. Thanks for posting this fix.

Talyn said:

The dreaded blend door issue is more isolated to WJs, not the XJ. You could also have a plugged heater core.

Click to expand...

Both hoses from heater core hot and equal in temperature. I wish the core was plugged, that would be an easier fix. The XJ is listed on the Heater Treater web page.

I ordered a Heater Treater kit at the end of January. The tracking number shows that package shipped a few days later and that's the last anyone saw of it.
Heater Treater did not insure the package and when I asked them to step up and ship another kit until the first one could be found they basically told me to pound sand. I initiated a dispute with Paypal and it was settled in my favor last week but I still need to repair my mixing door.
I could use some direction on where to cut the heater box to get at the valve. Does anyone have a photo or clear directions for this?