AC Cars & Trucks - Page 9 - Recent Questions, Troubleshooting & Support

what is year--make--model? If asd relay, I guess dodge or chrysler vehicle. Make sure battery has a full charge and battery connections all good. Pull asd relay, use jumper wire on switch side of relay, that should send voltage to everything the asd relay controls, see if it will start and run? Also check cam and crank sensor signals. How long since a tune-up? Any applicable trouble codes?

The AC stops ... the engine stops .... which I wonder.

Probably something going on with the blower motor control Processor . Hooking a scan tool an checking for DTC'S - diagnostic trouble codes would be the first step in a diagnostic procedure for a problem like this . Auxiliary Blower Motor Control Processor The auxiliary blower motor control processor is an interface between the auxiliary HVAC control module and the rear blower motor. The auxiliary blower motor control processor monitors supply voltage and ground circuits to the rear blower motor. The auxiliary HVAC control module provides a pulse width modulation (PWM) signal to the control processor in order to command the blower motor speed. The auxiliary blower motor control processor uses the blower motor ground as a low side control to adjust the blower motor speed. The blower motor forces air to circulate within the vehicles interior. The vehicle operator determines the blower motors speed by placing the blower motor switch in a desired speed position or by selecting automatic operation. In manual operation, once a blower speed is selected, the blower speed remains constant, until a new speed is selected. In automatic operation, the HVAC control module will determine what blower speed is necessary in order to achieve or maintain a desired temperature. As the requested blower speed increases, the following conditions occur: • The HVAC control module increases the amount of time that the blower motor speed control circuit is modulated to ground. • The voltage and duty cycle, measured between the blower motor speed control circuit and ground, decrease. As the requested blower speed decreases, the following conditions occur: • The HVAC control module decreases the amount of time that the blower motor speed control circuit is modulated to ground. • The voltage and duty cycle, measured between the blower motor speed control circuit and ground, increase.

ac condensers are in front of the radiator so anything that prevents the condenser from lifting up and out or out from the bottom could include bonnet release assembly and frame

Make sure your low pressure limit switch is good and being made.

Might not be the relay, there is a low side cutoff sensor on the return line. IF there is not enough Freon in it, the cutoff will open and the compressor wont start.

DTC P0480: Cooling Fan Relay 1 Control Circuit Circuit/System Description The engine control module (ECM) commands the fans ON in high speed or low speed. In low speed, the fans are configured in series. In high speed, the fans are configured in parallel. In low speed operation, the ECM applies ground to the coil side of the low speed relay. Voltage is applied directly to the left cooling fan through the switch side of the low speed relay. The right fan is connected in series to the left fan through the de-energized series/parallel relay, which is the FAN CNTRL relay, so that both fans operate at low speed. In high speed operation, the ECM applies a ground to the coil side of the low speed relay, the series/parallel relay, and the high speed relay. Voltage is applied directly to the right cooling fan through the switch side of the high speed relay. The left cooling fan obtains voltage through the low speed relay and ground through the series/parallel relay. When the ECM is commanding a fan relay ON, the voltage of the control circuit should be low, near 0 volts. When the ECM is commanding a fan relay OFF, the voltage of the control circuit should be high, near battery voltage. If the ECM detects that the actual voltage of the relay control circuit is different than the expected voltage, DTC P0480 or P0481 will set and the affected ECM driver will be disabled. Conditions for Setting the DTC • An improper voltage level has been detected on the cooling fan relay control circuit. • The condition must be present for a minimum of 30 seconds. Circuit/System Testing Ignition OFF, disconnect the 3 cooling fan relays listed below. • FAN LO relay • FAN CNTRL relay • FAN HI relay Ignition ON, verify that a test lamp illuminates between the ignition circuit terminal 85 of each relay and ground. ? If the test lamp does not illuminate, test the ignition circuit for a short to ground or an open/high resistance. Verify that a test lamp does not illuminate between the ignition circuit terminal 85 and the control circuit terminal 86 of each relay. ? If the test lamp illuminates, test the control circuit for a short to ground. If the circuit test normal, replace the ECM. Remove the test lamp. Ignition ON, command the affected relay ON using a scan tool. Verify the affected scan tool FC Relay Control Ckt. Short Volts Test Status Parameter is OK. • For the FAN LO relay, use the scan tool Fan Relay 1 command. • For the FAN CNTRL and FAN HI relays, use the scan tool Relay 2 and 3 command. ? If not the specified value, test the control circuit for a short to voltage. If the circuit tests normal, replace the ECM. Install a 3A fused jumper wire between the control circuit terminal 86 and the ignition circuit terminal 85. Command the affected relay ON with a scan tool. Verify the scan tool Relay Control Ckt Short Volts Test Status Parameter is Fault. ? If not the specified value, test the control circuit for an open/high resistance. If the circuit tests normal, replace the ECM. If all circuits and the ECM test normal, replace the affected relay.

Did you use a volt meter to test voltage drop on starter circuit ? It's easy to get aggervated When you don't know what your doing . Starter Voltage Drop

check your cooling fan...

That would depend on if it left the factory with A/C or not. If it did, you will just need to find out what part of the system has failed and repair it and have the system recharged. If it didn't leave the factory with A/C, it would probably be much easier to install an aftermarket kit like Vintage Air than it would be to try to install all of the components from one vehicle to another as the condenser, compressor, lines, wiring, controls, and evaporator core would definitely be more money than the truck would be worth.

what vehicle...depending on vehicle fan should come on with A/C and when the temp rises some have 2 fans one is just for the A/C

I assume you are talking about mercedes c300. Is that happening when you set on auto. What happens when you set temperature to lowest settings? When it blows hot, is it hot or warm? Does ac compressor works when you blow hot air? There could be few possibilities: low freon, faulty temperature sensor in the cabin, faulty ac controller, sticky ac/heater door or faulty door motor

Likely pulley is a problem not belt. Bad bearing or bushing could be a problem

Most Good auto parts dealers will be able to supply you with the correct size belt if you have the vehicle details with you.

Might try disconnection of battery as link below https://www.chryslerforum.com/forum/chrysler-pacifica-15/2004-chrysler-pacifica-climate-control-problem-29267/ https://www.youtube.com/watch?v=BcDg-5kkCzE https://www.youtube.com/watch?v=0iOTjoVDy48 click on see more on link below https://www.youtube.com/watch?v=0iOTjoVDy48

Probably a feed connection has been disconnected. Check the high pressure switch and low pressure stitches for a good connection. Also the compressor plug. Depending on the belt route, you may have the compressor running backwards. I have seen it happen.

Can you be more specific. Not blowing cold, not blowing at all, switch light not coming on etc?

U havva switch problm or relay bad Also inspect wiring. Cud b a bad module too. If car is oldr..unplug computer n clean the contact..they often git corroded. Purchase a repairbook at parts

https://www.fixya.com/cars/t9634455-compressor_clutch_relay_f25o_2002 Here is a previous response from fixya.

Check on the dryer (near firewall)