AC works partially, depending on low or high setup

ANSWER : The AC system uses a variety of actuators inside the ducting system in the car which control things such as what vents are used and whether the air is hot or cold. It seems most likely that the mode selector actuator has failed for you car. When this occurs, it exhibits symptoms like you have described. If you want to have this verified, a qualified technician from YourMechanic will be able to diagnose your AC issue and perform any repairs that may be required.

ANSWER : Hi there. In both cases, when an AC system is not working and a warning light is coming on the dashboard, typically a professional mechanic will complete the same initial inspection, which is to download the stored error codes that triggered the warning light initially. This tends to give them an idea as to what is causing the problems. This could be something as simple as an electrical relay that is faulty or loose or an indication of a computer related "glitch". Either way, the best way to move forward is to have a professional mobile mechanic complete a check engine light inspection.

ANSWER : As unfortunate as it is, your vehicle would be considered flood damaged. Diagnosing electrical problems in a flood damaged vehicle is nearly impossible. This would take many hours or even days to determine which wiring harnesses and circuits have been affected. Then nearly all of the wiring under the dash would likely require replacement as well as many sensors and switches. On a BMW vehicle, the amount of wires and switches are likely more than that of a lower end vehicle. Due to the inefficiency in cost, you would likely be able to purchase another BMW like yours for less than what it would cost to fix your car. Many insurance companies would consider this type of damage to total out the vehicle unfortuantely.

ANSWER : Hey there, thanks for writing in about your 2007 Mustang. The low beam circuit is monitored by the the Smart Junction Box. It’s the fuse box in the right kick panel. Basically what this means is if the resistance, or the current flow in the circuit is not within the specified range, it will turn off the power to it. That’s why you won’t find a fuse for the low beams. It will re-check the circuit every time the ignition key is cycled. The circuit flows from the SJB through the fuse box under the hood, and then to the headlights. Inspect as much of the wiring as you can. Especially where it might have been tampered with for the HID lights. If there is a short to power or ground, or too much or not enough resistance, it will turn off the power. This is not the case with your fog lamps and high beams. They are powered by a relay that is fused, and the circuit is not monitored. It will simply blow a fuse if there’s a problem. If you need more help, consider YourMechanic, as a certified technician from YourMechanic can come to your car’s location to diagnose and repair the headlight problem.

ANSWER : Hi There,
It sounds like you may have a faulty blower motor resistor. The highest speed setting may still work because in most cars in the highest fan speed settings the current bypasses the blower motor resistor. In some cars, if the resistor is failed, the fan may stop working completely. Another reason a blower motor resistor may fail is when the blower motor has a mechanical problem or when a foreign object jams the blower motor fan blade and prevents it from spinning freely. This leads to increased current through the resistor and causes it to overheat and fail. I would suggest having an expert from YourMechanic come to your location to diagnose your system to determine what may be causing the fan not to work properly.

ANSWER : Hi there. Check the switch to the headlights and see if there is a break in the wiring. Check the fuses and see if there is any fuse that are blown. If the fuses are good and there is no break in the wiring, then either the switch has failed or the ballast resister has failed on the low beam circuit. Turn on the switch and check for power coming out of the switch. If there is power to the switch and power out of the switch, then I recommend replacing the ballast resister. If there is no power coming out of the switch, then the switch needs replaced. If you need further assistance with diagnosing the low beams, then seek out a professional, such as one from Your Mechanic, to help you.

ANSWER : Hello. There are 2 devices in the front wiring of your vehicle called "Signal Acquisition Modules." One is for the left side of the front, the other is for the right. They act as an electrical "router" and power distribution module for electrical loads up front. These modules take signal pulses from light switches and other controllers, and turn on power to the requested device.

The SAM units have fuses in them, just as a traditional box would. I would check the fuses in each SAM for both low and high beams, then check the igniters for the xenon low beams. If this seems a bit intimidating, I recommend having a certified mechanic, such as one from YourMechanic, come to your location to inspect for any electrical problems and suggest the needed repairs.

ANSWER : Hi there. I have not seen a fuse box fail very often on this vehicle. It is possible that he meant to say that the fuse for the AC is blown which makes a lot more sense. Most of the time when the AC fuse blows it is because the compressor is failing and has a short in the clutch.

The circuit is going to have to be tested for a short to confirm why the fuse blew. It can take some time to trace the wires, though it is probably the compressor. If you need to have this diagnosed, consider YourMechanic, as a certified mechanic can come to your home or office to inspect your AC system.