The automatic climate control system in my 96 Grand Marquis makes a clicking noise. I tried turning the temp gauge up, but it maxes out at 90 degrees. Anyway to manually override this?

check fuses then find out if the actual climate control is not working replace if not. test for power and resistance.

Its probably going to be the fan resistor. Most times it is on top of the fan itself but could be elsewhere behind dash. 90% sure thats your prob though.

Sounds like freon is low/or has moisture in it and is having to build up pressure before engaging.

It sounds like thermostat (in coolant system) needs to be replaced. They only control you have for temps are the dials on dash, but if coolant thermostat is sticking you're limited to what it outputs. Replace coolant thermostat and you should be "good to go"

Try setting the climate control to "Automatic," then raise the temperature until the display reads what you want, like 72 or 74 degrees. The heat will come on automatically and adjust by itself when the temperature you set is reached. You can also push the "Floor" or :Defrost" button and this will turn the heat or defrost on manually.

Check your antifreeze with a antifreeze checker to make sure it is at the right temp depending on where you live and how cold it gets there. If you have too much antifreeze the engine temp will not come up to over 200 and also replace your thermostat, making sure to realize they make them in different temp settings. Talk to people and make sure the thermostat you install is the right one for your climate where you live. Sounds to me as though your temp never comes up to what it should be. Also it could be the heater core.

This is a chronic problem with Grand Cherokees. The blend doors inside the air box in the dash fail over time. This is caused by cheap plastic parts used by Chrysler that break easily.

Your problem is the forth Jeep I have seen like this in the past 2 months.

To check your climate control system for fault codes do this:

-Turn key to 'on'
-press and hold 'a/c' and 'recirc' buttons and turn drivers side temp knob clockwise one click.

Now the display will show 0 if no codes are present or one or more numbers if something is wrong.

You can check what these codes mean here: http://www.wjjeeps.com/climate.htm

Reply back with results.

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it is possible the thermostat is the problem, but if it is stuck closed the engine coolant temp gauge (if you have one) would show an overheat reading. most temps gauges will read 195 to 205 degrees. the other possibility is if you have an automatic climate control system, the blend door motor may have failed and will not adjust correctly to the temperature you have set for the interior

electic fan relay or coolant temp sensor will be ur problem if its not a fuse

1st Thing,
Located Someone With a Set Of A/C Gauges 134A Freon,
Make Sure Your A/C System Has Enought Freon In It, There Is a Low Freon Pressure Switch
In The Electrical System, Usually, 50-60 PSIG or Less On The Gauges, Will Indicate Low Freon, When Freon Is Low The Compressor Is Dis-engaged To Prevent Compressor Damage.
1] Low Freon
2] Bad Low Pressure switch
3] Blowen Fuse[s]
4] Electrical Problem[s]
[a] Digital Climate Controlled ?
Climate Control Self Diagnose From Button's On Unit, OEM Manual Explains This,
If Yor Auto Has Digital Climate Control.
5] Bad Compressor DC Coil

Note: Does The Compressor Engage, Click-On When Button Is Pressed, But Getting
Only Warm Air?
Is One Of The Compressor Aluminum Tube's Cold, Be Careful Other Is Really Warm/Hot,
If Cold and or Sweating, Dripping Water [Normal], You Are Blending Hot Air w/Cold
Air At The Heater Blend Box, Making Warm Air.
If This Is So, If A Vaccum Controlled Temp Unit, Check For A Vaccum Hose Bad,
Should Be Either 1or 2 Vaccum Lines Going Into Firewall To Feed The Controller
Unit, If OK, Might Be a Bad Blend Box Diaphram, [Control's A/C air, Blocks Off
heater Coil Hot Air].
If Your Auto Is Vaccum Controlled, Can You Changed From Bottom, Dash,
Defrost Air Flow?, Yes, No Vaccum Lost Feeding Controller, Still Might Have
Bad Diaphram Blending Hot Air w/Cold If Your Have Cold Alum-Tubing In
engine Compartment.
If Digital Climate Controlled, Might have Diaphram's, Vaccum Controlled or
electrical Servo's Controlled vs Diaphram [Vaccum] Controlled.
This Might Help, Hopefully, This Is Just For Starter's, There More To Some System's
and Without The OEM Mgr's Manual[s] You/Be Would Be Lost, especially w/Electrical.
Later, God Bless