Hvac fan runs intermittenly or not at all. It will go from low blow to high to nothing, with air or heat running. Temp contol mod. or relay?

Both radiator cooling fans are running all the time ? Key off ? The cooling fan opperation
HOW they work
Cooling Fan Control
The engine cooling fan system consists of 2 cooling fans and 3 relays. The relays are powered by the battery positive voltage circuit and controlled by a switched ground from the powertrain control module (PCM).
During low speed operation, the PCM supplies the ground path for the low speed cooling fan relay through the low speed cooling fan relay control circuit. This energizes the cooling fan low relay coil, closes the relay contacts, and supplies battery positive voltage from the COOL FAN LO fuse through the cooling fan motor supply voltage circuit to the cooling fan. During high speed operation the PCM supplies the ground path for the cooling fan low relay through the low speed cooling fan relay control circuit. After a 3-second delay, the PCM supplies a ground path for the cooling fan high relay and the s/p cooling fan relay through the high speed fan relay control circuit.
The PCM commands the fan on under the following conditions:
• Engine coolant temperature exceeds approximately 98°C (208°F) Low Fan Speed
• Engine coolant temperature exceeds approximately 102°C (216°F) High Fan Speed
• A/C refrigerant pressure exceeds 361 kPa (52 psi) Low Fan Speed
• A/C refrigerant pressure exceeds 2100 kPa (300 psi) High Fan Speed
• When the engine coolant temperature exceeds 112°C (234°F) at key off, the fan high speed will run for up to 300 seconds. If within that time frame 102°C (216°F) is reached then fan speed will change from high to low speed. If within that time frame 99°C (210°F) is reached then fan speed will change from low to off.
The PCM commands the fan off under the following conditions:
• A/C is requested and engine speed exceeds 6,240 RPM
• Engine coolant temperature exceeds approximately 99°C (210°F) turns the cooling fans from low to off.

sounds like one of the relays are stuck closed .

Cooling Fan Always On
Step
Action
Yes
No
Schematic Reference: Engine Cooling Schematics , HVAC Schematics in HVAC Systems - Manual
Connector End View Reference: Cooling System Connector End Views
DEFINITION: One or both engine cooling fan motors run continuously in high or low speed.
1
Did you perform the Diagnostic System Check - Vehicle?
Go to Step 2
Go to Diagnostic System Check - Vehicle in Vehicle DTC Information
2
Install a scan tool.
Turn ON the ignition, with the engine OFF.
With a scan tool, command the Fans Low Speed ON and OFF.
Are one or both cooling fans ON?
Go to Step 3
Go to Testing for Intermittent Conditions and Poor Connections in Wiring Systems
3
Are both cooling fans running continuously?
Go to Step 4
Go to Step 6
4
Are both cooling fans running continuously in high speed?
Go to Step 5
Go to Step 7
5
Test the low reference circuit of the A/C refrigerant pressure sensor for an open. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.
Did you find and correct the condition?
Go to Step 18
Go to Step 14
6
Important: The S/P relay is located under the front bumper on the drivers side of the vehicle.
Remove the cool fan S/P relay.
Did the right cooling fan turn OFF?
Go to Step 10
Go to Step 8
7
Remove the cool fan LOW relay.
Did the cooling fans turn OFF?

no the pipes should not be cold and wet but if you just have stop using the aircon recently it will do that for a while till all the gas is out of the system so yes its sorta normal

If you are referring to the fans both running when the A/C is on, if the high side of the system (condense temp) does not get to a certain temp calling for the second fan, it will not turn on. The single fan running without A/C would normally be for cooling the engine temp (antifreeze).

I would look at the A/C condenser fan or the switch that triggers it and test for power/function. It sounds like the gas isn't condensing due to lack of air flow, until it gets enough at speed to exchange heat through the condenser and bring the temps down.

HINT 1:check fuses first???????
NO ENGINE STATED AND WORK DIFFERENT.
the free FSM book is here
https://www.jeepdied.com/
read that? HVAC and cooling chapters.

heater does not blow hot air AT VENTS.
does that mean blower dead?

is hot AIR knob at hot zone.?
is fan on high, :"?
can you hear a normal sounding fan on high???????
does it fail in recirc mode and vent??
Does hot are work with car moving fast?
is engine at 180f or more>using tools to measure rad temp?
OR LEARN TO USE SCAN TOOLS
SEE ECT AT 180F+ AND KNOW AT FULL TEMP.
yes,/no, if engine is hot, and AF LEVELS ARE FULL
did you scan the pcm for hvac errors (DTC)
Then this is a HVAC failure.
some GC have a hvac calibrate mode, read the Fsm ON THIS.
some have the climate control option, do you,????? very important fact to know.

EVER FLUSH THE COOLANT SYSTEM IN 12 YEARS.
HUMMMMMMMMMMMMMMMMMMMMMMMMMMM

WJ JEEP (got AZC?)
2002
HEATING CHAPTER, READ THAT?
see wiring-air-cond.......

http://www.morris4x4center.com/knowledge-base/index.htm?utm_source=cj#service

IF THE BCM CAN NOT TALK TO THE AZC
guess what. things fail
scan it
no scan it twice. and win..
only with AZC OPTION
SEE ALL THOSE lines bottom
lots of damper motors on each
COMPLEX. diagnosis. if present.
SEE PIN 4 BLEND


the Mtc WORKS TOTALLY DIFFR
The TVA below runs the blend door. motor. unlike aBOVE.


LOTS more IN THE BOOK.

check fuse first
then scan PCM , oops you didnt and the BCM does run this stuff.
so not scanning it , you miss all those FACTS.

the blower is dead. (aka , not spinning , or silent)
on all cars made the answer is the same.
blown fuse, fuse marked BLower, is blown. LOL.
controls not turning it on, controls failure.
blower bad. (motor) hot wire it in place to test)
wires to any of the above.
or the resistor block bad, (if it works on high but not low)
i have the schmematic in hand.

the HVAC relay pulls in by command of the BCM
the relay then sends 12vdc power to the blower via fuse 41
the blower is now hot full time.
the blower then needs a ground to spin (run)
on high, the ground G601 via the speed knob,switch makes that ground connection, so if the fan dont spin and say the fan is ok
then the relay is not closing or the fuse 41 is blown. (why not look at the fuse first for all electric fails)
the BCM sees you, turn fan on, (heat or cold)
and closes this relay, on the left.
if the relay does not close, (and coil is ok inside)
the the BCM didnt see those HVAC requests.
use a scan tool and look for BCM errors..>??????

On any other vehicle it sounds like the blower fan switch.
The fan switch provides power or ground to the resistor and there would be a high speed blower relay to bypass the resistor.
But in your case the fan switch is part of the controller.
I don't have a diagram for a 92 but the 94 model shows relays for low medium and high speeds. Each relay gets power from a fuseable link. The high relay gets power thru the low relay if the low relay is not engaged.
If you have the model with 3 relays you may need to check them.

Hello: You need to remove the passenger side glove box. Behind it you will see the HVAC programmer. On the top you will see a silver linkage that goes from the programmer to a linkage on top of the HVAC case. That linkage attaches to the air mix (temperture) door. withe car running and climate control on move the temp setting from 60 to 90, the linkage should move. If it doesn',t Reach in and with your fingers move the linkage, if it moves (toward the driver side) then that means you have a bad HVAC programmer. You used t be able to get a new actuator motor and repair the programmer but I don,t know if its available anymore or not. The actuator was a high failure item. Note: HVAC stands for "HEATER VENT AIR CONDITIONING" If you secure the linkage towards the driver side you should get heat but no automatic control or no way to reduce the amount of heat but you would have heat till you find the part.

Switch the relay with one of the other relays to make sure that this relay is good then go to the HVAC control programer which is behind the floor vent (middle). The Blk/gray wire is the one that supports the relay coming out of the HVAC programmer, but there is a chance that this programmer is bad. If that proves to be the case, I may even have one...let me know.

the compressor may be low on freopn but, the fan problem is most likely the fan motor as it is the low temp fan and will run more often than both fans...to test see if you can switch the fan plugin to the other fan watch carefully that it does not get too hot as the second fan is a safety fan that works as high temp or when using the A\C