My air cond ic box not function well and i can only use switch 4 for the air cond cooling coil fan speed. switch 1, 2 and 3 recently cannot function at all. before this switch 2 and 3 works like switch 1 speed only. where to get 2nd hand if the new is too costly. or can repair ?

The engine cooling fan system is controlled by the body control module (BCM) and the powertrain control module (PCM) or engine control module (ECM). The BCM performs the calculations as to how long, when and what speed the cooling fans should turn on. The BCM then sends a class 2 message to the PCM/ECM to engage the cooling fan relays. If there is a malfunction with the BCM, the PCM/ECM will control the engine cooling fans independently. The engine cooling system consists of 2 electrical cooling fans and 3 fan relays. The relays are arranged in a series/parallel configuration that allows the PCM/ECM to operate both fans together at low or high speeds. The cooling fans and fan relays receive battery positive voltage from the underhood accessory wiring junction block. The ground path is provided at G100.
During low speed operation, the PCM/ECM supplies the ground path for the low speed fan relay through the low speed cooling fan relay control circuit. This energizes the cooling fan 1 relay coil, closes the relay contacts, and supplies battery positive voltage from the cool fan 1 fuse through the cooling fan motor supply voltage circuit to the left cooling fan. The ground path for the left cooling fan is through the cooling fan 2 relay and the right cooling fan. The result is a series circuit with both fans running at low speed.
During high speed operation the PCM/ECM supplies the ground path for the cooling fan 1 relay through the low speed cooling fan relay control circuit. After a 3 second delay, the PCM/ECM supplies a ground path for the cooling fan 3 or S/P relay and the cooling fan 2 relay through the high speed cooling fan relay control circuit. This energizes the cooling fan 2 relay coil, closes the relay contacts, and provides a ground path for the left cooling fan. At the same time the cooling fan 2 relay coil is energized closing the relay contacts and provides battery positive voltage from the cool fan 2 fuse on the cooling fan motor supply voltage circuit to the right cooling fan. During high speed fan operation, both engine cooling fans have there own ground path. The result is a parallel circuit with both fans running at high speed.
The BCM and PCM/ECM command Low Speed Fans on under the following conditions:
?€¢
Engine coolant temperature exceeds approximately 106?°C (223?°F).

?€¢
A/C refrigerant pressure exceeds 1 310 kPa (190 psi).

?€¢
After the vehicle is shut off if the engine coolant temperature at key-off is greater than 140?°C (284?°F) and system voltage is more than 12 volts. The fans will stay on for approximately 3 minutes.

The BCM and PCM/ECM command High Speed Fans on under the following conditions:
?€¢
Engine coolant temperature reaches 110?°C (230?°F).

?€¢
A/C refrigerant pressure exceeds 1 655 kPa (240 psi).

?€¢
When certain DTCs set.

The three relays are located in the under hood fuse / relay box ! You need to have it checked for DTC'S -diagnostic trouble codes ! An you need a GM Tech 2 scan tool !
This diagnostic procedure supports the following DTCs:
?€¢
DTC P0480 Cooling Fan 1 Relay Control Circuit

?€¢
DTC P0481 Cooling Fan 2 and 3 or S/P Relay Control Circuit

?€¢
DTC P0691 Cooling Fan 1 Relay Control Circuit Low Voltage

?€¢
DTC P0692 Cooling Fan 1 Relay Control Circuit High Voltage

?€¢
DTC P0693 Cooling Fan 2 and 3 or S/P Relay Control Circuit Low Voltage

?€¢
DTC P0694 Cooling Fan 2 and 3 or S/P Relay Control Circuit High Voltage

1. Install a scan tool.
2. Turn ON the ignition, with the engine OFF.
3. With a scan tool, command the Fans Low Speed ON and OFF.

Do the low speed engine cooling fans turn ON and OFF with each command?
Go to Step 3
Go to Step 4

3

Important:: A 3 second delay occurs before the powertrain control module (PCM)/engine control module (ECM) changes the cooling fan speed.
With a scan tool, command the Fans High Speed ON and OFF.
Do the high speed engine cooling fans turn ON and OFF with each command?

The engine cooling fan system consists of 2 electrical cooling fans and 3 fan relays. The relays are arranged in a series/parallel configuration that allows the powertrain control module (PCM) to operate both fans together at low or high speeds. The cooling fans and fan relays receive battery positive voltage from the underhood accessory wiring junction block. The ground path is provided at G113. The relays are located in the underhood fuse / relay box .
So ,what's the problem Paul , car overheating ? Fans not working ?
During low speed operation, the PCM supplies the ground path for the low speed fan relay through the low speed cooling fan relay control circuit. This energizes the cooling fan 1 relay coil, closes the relay contacts, and supplies battery positive voltage from the cool fan 1 fuse through the cooling fan motor supply voltage circuit to the right cooling fan. The ground path for the right cooling fan is through the cooling fan 2 relay and the left cooling fan. The result is a series circuit with both fans running at low speed.
During high speed operation the PCM supplies the ground path for the cooling fan 1 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 2 relay and the cooling fan 3 relay through the high speed cooling fan relay control circuit. This energizes the cooling fan 2 relay coil, closes the relay contacts, and provides a ground path for the right cooling fan. At the same time the cooling fan 3 relay coil is energized closing the relay contacts and provides battery positive voltage from the cool fan 2 fuse on the cooling fan motor supply voltage circuit to the left cooling fan. During high speed fan operation, both engine cooling fans have there own ground path. The result is a parallel circuit with both fans running at high speed.
The PCM commands Low Speed Fans on under the following conditions:
?€¢
Engine coolant temperature exceeds approximately 106?°C (223?°F).

?€¢
When the A/C is requested and the ambient temperature is more than 50?°C (122?°F).

?€¢
A/C refrigerant pressure exceeds 1310 kPa (190 psi).

?€¢
After the vehicle is shut off if the engine coolant temperature at key-off is greater than 140?°C (284?°F) and system voltage is more than 12 volts. The fans will stay on for approximately 3 minutes.

The PCM commands High Speed Fans on under the following conditions:
?€¢
Engine coolant temperature reaches 110?°C (230?°F).

?€¢
A/C refrigerant pressure exceeds 1655 kPa (240 psi).

?€¢
When certain DTCs set.

So

dodge fan heat-cool system uses resistive coils to control fan-speed. the module is located under the windshield. take off wipers, fresh air vent, look for a box with 2 coils in it. 1 thick and 1 thin.

Couple of reasons. You may need to have the Radiator backflushed to remove sediment. You also have an Electric cooling fan which may be malfunctioning. They (fans) often have more than 1 speed and high speed may be broken so it can not keep up with extreme heat.

Some fans use more than 1 relay to switch the fans and the second stage relay may be bad.

Overall, the A/C coil is placed in front of the Radiator and depends on airflow to function. This makes the air available to the Radiator much hotter so the Radiator is having a hard time cooling the engine. The Electric radiator fans kick up the airflow to help both systems out.

A dirty radiator, old antifreeze, etc. can affect performance.

I hope my solution is helpful. Radiator shops can service most Brands.

The problem is the blower motor speed control resistor, it is located near the blower motor in the housing. I exchanged mine and it works like a charm now.

Hope this helps your out. I know the diagram and locator is a bit blurry but hopefully it gets what you need.
Drivers kick panel:
Front wiper 20A - Front wiper system Cigar 15A- Cigarette lighter Audio 10A- Audio, remote control mirror Air Bag 10A -Air bag diagnostics Stop lights- 15A -Rear brake light, high mounted stop light ECU B+ 10A - Shift lock actuator, transaxle controle module, radio, engine control module Room 10A - Interior light, clock, ignition key reminder, rear cargo area light switch ABS 10A- Anti lock brake system control unit ECU IG1 10A - Transaxle control module, shift lock actuator, ABS control unit, DRL unit Meter 10A - Instrument panel, back-up switch, electronics time control module, inhibit switch Turn signal 10A- Hazard switch ,front and rear turn lights, turn indicator IGN1 20A - Ignition switch ABS 30A- ABS pump motor TNS 30A- Tail light, license plate light COOL/FAN 30A- Cooling fan Cond/Fan 20A- A/C condenser fan Starter 15A- Start signal , Fuel pump Blower 25A- Blower Motor SR/ACC 10A - Ignition switch Hazard 15A - Hazard and turn signal light D/Lock 25A- Door locks ABS 30A - Anti lock brake system control P/W RH 20A- Power window motor right hand P/W LH 20A- Power window motor left hand IGN2 25A- Ignition Switch
Engine compartment :
Head 25A- headlights IG 2 30A- Ignition switch IG coil 15A -Ignition coil, condenser,generator IC regulator, diagnostic connector. O2 down 10A- Rear O2 sensor O2 up 10A- Front O2 sensor Fuel pump 10A -Fuel pump unit Injector 10A -Fuel injector ,camshaft positioning sensor, purge solenoid valve, EVAP, IAC actuator, Mass Airflow sensor, EGR stepper motor. fuel pump relay coil, vehicle speed sensor. A/Con 10A - A/C compressor controls, cooling fan BTN 30A- Brake light , high mounted stop light. Tail light LH 10A- License plate light, tail light , rear combo light, instrument panel illumination Tail light RH 10A-License plate light, tail light , rear combo light, instrument panel illumination Head low 15A- Headlight Head Hi 15A-Headlight Horn 15A- Horn

Inside kick panel

A bad blower moter resistor can cause the blower to have high speed only. A bad fan switch can
also be the problem, but the resistor is the more common culprit. As I don't know the model+year
you've got, I can only give you a couple of the most common locations for the resistor block on the
town+country van style it's under the hood on the right firewall. On the cars it's on the lower right of
the heater box under the dash. And you know where the switch is. Hope this helps.

There is a high pressure switch on the high side of the ac system,it most likely is bad.

AC's have a low freon switch that shuts off the system to protect the compressor in the advent that you have a freon leak have the system checked for a leak

thank you so much u helped me fix my heat it was that white thing under the clove box it had a bad connection...thank u so much we couldn't figure out what was wrong.