No cold air

Hi there,

If this vibration is only when the A/C is turned on the compressor may be failing,

Let use this guide to see whats going on

https://www.2carpros.com/articles/car-air-conditioner-not-working-or-is-weak

Please run down this guide and report back. Mark (mhpautos)

Check coolant level then pressure check for leaks. Cold be a charging problem as well or check battery terminals for being clean and tight. Or a bad body to battery ground.

Check the fuses inside and under the hood. You did not say which wire you shorted. If it was for the radio's memory, that is always tied into some other circuit that is always live. Interior lights are used most commonly, but it could also be the horn, brake lights, cigarette lighter, or another computer memory circuit. The HVAC Computer could be involved.

Some radios will be totally dead if the memory 12 volts is missing. Some will only have no sound. They will light up and tune a station. Others will work perfectly fine except each time you turn them on they will reset to 12:00 or 10:00 and the station will go back to a factory preset.

Glad we can help please use 2CarPros anytime we are here to help

Best, Ken

Hi there,

The first thing you need to do is get the system pressures tested, this will give the tech a good idea as to what is going on in the system.

Mark (mhpautos)

Check the blower motor fuse. If good, check for power at the blower motor itself with the ignition ON and the blower speed setting on HIGH.

An A/C system that blows cold air for awhile then warm air is probably freezing up. This can be caused by air and moisture in the system that allows ice to form and block the orifice tube.

Evacuating the system with a vacuum pump will purge it of unwanted air and moisture. Evacuation should be done with a vacuum pump that is capable of achieving and holding a high vacuum (29 inches) for at least 30 to 45 minutes.

For best performance, an A/C system should contain less than 2% air by weight. For every 1% increase in the amount of air that displaces refrigerant in the system, there will be a corresponding drop of about one degree in cooling performance. More than 6% air can cause a very noticeable drop in cooling performance, and possibly cause evaporator freeze-up.

Air can get inside a system through leaks, by not evacuating the system prior to recharging it, and/or by recharging the system with refrigerant that is contaminated with air. Recovery equipment can suck air into the recycling tank if an A/C system contains air or if the system has a leak. For this reason, the refrigerant recovery tank on recycling equipment must be checked and purged daily. On some equipment, this is done automatically. But on equipment that lacks an automatic purge cycle, tank pressure and temperature has to be measured and compared to a static pressure reference chart.

Some refrigerant identifier equipment can detect air in the system as well as other contaminants. An identifier should be used to check the refrigerant before the system is serviced to prevent cross-contamination of recovery and recycling equipment.

Possible causes of intermittent cooling in a manual A/C system that might be caused by an electrical problem include:

Faulty low pressure cutout switch. This switch prevents the compressor from running if the refrigerant level is low. If the cutout switch is not reading correctly, it can prevent the compressor from coming on.

Faulty compressor clutch. The magnetic clutch on the compressor requires full battery voltage to engage. If the voltage to the clutch is low, or the clutch coils have too much resistance, or the air gap in the clutch is too great, the clutch may not engage to drive the compressor.

Faulty compressor clutch relay. Check to see if the relay is receiving voltage when the A/C is turned on. Also check the relay wiring and ground connections. If bypassing the relay with a jumper wire or routing battery voltage directly to the compressor clutch makes the A/C work, the relay is probably bad.

Faulty A/C control switch. The switch may be worn and not making good contact when it is turned on.

Some possible causes of intermittent cooling (or no cooling) on automatic A/C systems include all of the above, plus:

A problem in the control module or control head (this usually requires using a dealer scan tool to read fault codes and perform self-diagnostics).

A bad temperature sensor (an ambient air temperature sensor, interior air temperature sensor, evaporator temperature sensor, or sunload sensor). Again, a factory scan tool is usually required to perform diagnostics on the system.

Instincts tell me it's just coincidence it won't start. The ac modification should have nothing to do with it unless you unplugged something you're unaware of.
You need to check to see what is missing. Spark, fuel pressure or injector pulse. Or, any combination of the three. Also, check the connection on the crankshaft position sensor. Please advise.

Ya' done good. Anything else, you know where to find us.

Hi ossiv99. Welcome to the forum. If you have 12 volts to the compressor, that just leaves ground and the clutch coil. I can't remember for certain, but I believe the coil is always grounded and the 12 volts switches on through a relay. That's the way most cars are wired. If that's the case, check the resistance to ground on the coil's ground wire and measure the continuity of the coil. One of those two has to be open.

To not overlook something stupid, did you measure the 12 volts with a voltmeter or a test light? If you used a voltmeter AND the connector was not plugged into the compressor, the results can be misleading. The voltmeter will not draw a significant amount of current, so pitted relay contacts that can't pass enough current to run the compressor clutch, will still allow the 12 volts to be seen by a voltmeter. A test light draws much higher current and will cause pitted contacts to show up as low or missing voltage to the coil. For older cars that used special wires for fusible links, the same thing can happen when the wire burns open and leaves a carbon track behind. No current will get to the clutch coil, but voltage will be measured by the voltmeter when the connector is unplugged.

Caradiodoc