What’s wrong with my van’s air conditioning system?

Q. I have an air conditioner issue with my 2013 Chrysler Town & Country van. I had a local mechanic take a look and we definitely have a leak in the rear evaporator unit. It requires a complete replacement that will cost $2,500. In the meantime, he charged the system back up and the air conditioner ran nice and cold until the blowers in the back of the van stopped working. Any thoughts about why the blower just stopped moving air?

A. Typically, when a blower fan stops working it is one of several possible causes. These can be the blower motor relay, open fuse, inoperative blower motor power module or resistor block, inoperative blower motor or switch, or wiring. I would return to your mechanic and have them check it out. 

Q. I recently purchased a key fob for my 2003 Volvo XC70 from an online store. It said it came with programming instructions. The instructions stated I would need to go to a Volvo dealer or locksmith. How do I program this remote key fob? 

A. Some vehicle key fobs can be easily programmed by locking and unlocking the doors and manipulating the key fob. Others require special tools and software to perform the programming. This is the case with your Volvo, so you will need to find a specialized automotive locksmith or return to the Volvo dealer to have the key fob programmed. 

Q. We are being asked to limit air conditioner use over the summer to prevent brown-outs, but also told it would be best to buy electric cars. Can you explain this? 

A. I have spoken with people who are responsible for the power grid, and they tell me that the grid is capable of supplying enough electricity for electric car charging. That is not to say that once electric cars occupy more than the current  4.5 percent of the market there may not be an issue, especially in the Northeast where we have some very old infrastructure. To help mitigate this potential issue, electric cars using a combination of smart metering and programmable charging can charge the battery during off-peak, low-use hours. In addition, electric cars may be able to act like a storage device for electricity to help manage the peak electrical demands. 

Q. Have you driven the new Ford F-150 Lightning electric truck yet? What did you think?

A. I did drive the Lightning truck, although just for a short test drive. So far it has exceeded my expectations. Like all new electric vehicles, it is fast, smooth and powerful. Ford also did a great job of utilizing the space in the truck. This includes the front trunk (frunk) which adds more enclosed lockable storage. During my limited test drive the handling was very good and the ride was firm but comfortable. Electric vehicles are not for everyone, but this one is quite good. 

Q. I have a 2014 Dodge Charger with the V-8 engine that I purchased from a fleet auction. The car runs great most of the time but sometimes it misses and sets a misfire code. I have changed the spark plug and ignition coil, but the problem is still there. I did a compression test of that cylinder and the one next to it and the compression was the same, so I assume the engine is okay. Any thoughts? 

A. This engine like many will deactivate some cylinders at certain times to improve fuel economy. This is called the multiple displacement system (MDS) and on this engine selectively deactivates cylinders 1, 4, 6 and 7 during steady speed, and low speed operation to increase fuel economy. The issue could be a faulty valve lifter or MDS solenoid. I have seen some issues even caused by using the incorrect viscosity oil. Some readers who have have written to me have fixed the issue with aftermarket tuning/programming to disable the MDS solenoids. 

Q. I have a 10-year-old Toyota and the blower fan only runs at low speeds. I know from reading your column that if it only ran at high speed, it would be the blower motor resistor. Why does it only work on low but not the other speeds?

A. I would start with powering the blower motor directly with 12-volts. You could do this by bypassing the resistor. If the blower spins fast, the issue is the wiring or the speed selector switch. If the blower doesn’t spin at high speed, it could be a faulty ground or the motor is binding up. 

John Paul is AAA Northeast’s Car Doctor. He has over 40 years of experience in the automotive business and is an ASE-certified master technician. E-mail your car question to [email protected]. Listen to the Car Doctor podcast at johnfpaul.podbean.com.