Where is the location of the coolant sensor in gran cherokee laredo 1997 -V6

They should be a welded receptacle - one just in front of the CAT and one just after the CAT. They usually have a teflon wire leading to them which is distinctly different than other wiring in the car.

no symptoms? at all, just a curiosity quesiton>?
THE ECT sensor for the PCM? that?
so 3.7L v6 , not the 3Liter Turbo Diesel.v6????

all this is covered in the FSM. to the nth degree.
and 100s of photos in google , image.
or at any dealer, the parts list and photos, of same online.
part ID 19 seen here.
any dealer has this page, in store or on line.

http://www.factorychryslerparts.com/showAssembly.aspx?ukey_assembly=559686&ukey_product=4305928

mounted to the coolant outlet fitting.

The temperature sensor is located:

The coolant temperature sensor is installed in the thermostat housing

Fig. The coolant temperature sensor is installed in the thermostat housing (click image for zoom).

1. Partially drain cooling system until coolant level is below cylinder head.
   
2. Disconnect coolant temperature sensor wire connector.
   
3. Remove sensor from thermostat housing.

Hope helps (remember to rate ths answer).

These are the fault codes for your Jeep below;

Jeep
11 IGN reference signal.
13 Fault in the map sensor pneumatic circuit.
14 Fault in the map sensor electrical circuit.
15 Fault in the vehicle speed sensor circuit.
17 Engine running too cool.
21 Problem in the oxygen feedback circuit.
22 Fault in the coolant temperature sensor circuit.
23 Air temperature sensor.
24 Fault in the throttle position sensor circuit.
25 Fault in the IAC motor drive circuit.
27 Fault in injector driver interface circuit.
31 Purge solenoid circuit.
33 Fault in air conditioning cutout relay circuit.
34 S/C solenoid circuits.
35 Fault in fan relay circuit.
41 Fault in the charging system or no field current.
42 Fault in the ASD relay driver circuit.
43 Fault in ignition coil control circuit.
44 Battery Temp Voltage.
46 Battery voltage is too high.
47 Battery voltage is too low.
51 Lean condition is indicated.
52 Rich condition is indicated.
53 Internal problem in module.
54 Fault in the distributor high data rate pickup circuit.
55 Completion of fault code display.
62 Unsuccessful attempt to update EMR mileage.
63 Unsuccessful attempt to write to an EEPROM location by the controller.
76 Fuel pump resistor by-pass relay circuit

Yes, cause that sensor operates the electric cooling fans by the radiator, if those fans or fan don't come on, the radiator can't cool down as quick and causes the engine to run hotter.

in the 5.2L V8 engine the coolant sensor is located on top of the engine. Locate the coolant thick hose coming from top of the ratiator to the top of the engine. Look at the place such hose connects to the engine you wont miss the sensor it is about one inch from there.

it is located under the battery in the battery tray.

If you have the v6 then you will find the coolant temp sendor near the thermostat housing below the throttle body and just toward the front of the vehicle near the coolant bypass pipe. If you have a 4 cylinder then look at the rear of the cylinder head near thermostat.
Good luck.

I would spend the money on repairing the coolant leak,do that first then concentrate on the other problems.The LR window problem is probably due to lack of use,give it some lube.I would guess the drivers door lock actuator is faulty or out of adjustment.