Have you been having problems with the heating system in your Jetta? If so, the following is a must read. We’re going to run go through some of the most common faults with heater systems and tell you how to fix them.
Note: The first thing you should do before looking more into these problems is to check the fuses in your car. If there is a fuse that’s blown, you should change it. You may find that this solves your problems. If the fuses are fine, read through the following list of common problems and their fixes.
Heater only working on certain settings.
You may find that the car’s heating will work fine on certain settings, such as 3 and 4, but there is nothing at all working on 1 and 2.
This is a sign that the blower motor resistor has worn out. The easiest way to fix this is to change the old resistor for a new one. They aren’t very expensive and can be purchased here.
Once you have the part, you need to remove the old resistor and install the new one. You will need to first remove the glove box to gain access to the blower motor resistor. This thread gives detailed instructions on how to do this. Once the glove box is removed, you can replace the part. This video is a good guide.
There is no heat coming out of the vents.
There are two main reasons for this. Either there is a problem with the thermostat in the heating system or the heater core has a blockage or air in it. To see which of these two problems is causing the fault, drive your car for a while and get it up to its working temperature. When the car is up to temperature, check the temperature gauge. If this looks low compared to normal, you have a problem with the thermostat. To double check this, check the temperature at the top hose of the radiator. If this is cool, it suggests that the thermostat is at fault. If the car is getting up to temperature,then there is an issue with the heater core.
Solution – Thermostat
The easiest way to fix this problem is to replace the thermostat. A new part can be purchased here in the “Cooling System” section for your specific year Jetta.
Before working on this system, make sure the car is cool and hasn’t been driven for at least an hour as the fluids in the cooling system need time to cool down.
This job can be a bit laborious, but it can be done at home. This video shows you the steps but make sure you watch it prior to starting the job as there are some parts that are tricky to reach and you may need to invest in some new tools.
Solution – Heater Core Blockage
You will need to flush out the heater core to remove any blockage that has built up over time. This video shows you how to do this using a regular garden hose. If you don’t feel confident doing this yourself, you can always take your vehicle to the dealer or an independent auto repair shop. If you are going to do this yourself, make sure the engine is cool before starting.
Vents feel warm but there is nothing forcing the air out.
If you can hear the fan turning when you change the setting, this shows that it’s working. If there is heat at the vents but no real movement of air, there’s a blockage in the system, most likely in the cabin air filter. These can get a build up of debris over time, especially if they haven’t been changed regularly.
This is an easy fix. A new filter will cost less than $20 and you can get one here under the “A/C & Heater” section, in the “Blower Motor” subcategory. This guide shows you the steps you to replace this part. It should only take about half an hour to complete.