Exception in rendering!

Message: window is not defined

ReferenceError: window is not defined
    at new c (/tmp/execjs20161209-75876-18tiu2bjs:136:3912)
    at m.mountComponent (/tmp/execjs20161209-75876-18tiu2bjs:47:15602)
    at /tmp/execjs20161209-75876-18tiu2bjs:49:31860
    at a.r.perform (/tmp/execjs20161209-75876-18tiu2bjs:47:12503)
    at Object.a [as renderToString] (/tmp/execjs20161209-75876-18tiu2bjs:49:31821)
    at r (/tmp/execjs20161209-75876-18tiu2bjs:50:21164)
    at Object.S.ReactOnRails.serverRenderReactComponent (/tmp/execjs20161209-75876-18tiu2bjs:32:6073)
    at eval (eval at <anonymous> (/tmp/execjs20161209-75876-18tiu2bjs:173:8), <anonymous>:10:23)
    at eval (eval at <anonymous> (/tmp/execjs20161209-75876-18tiu2bjs:173:8), <anonymous>:17:3)
    at /tmp/execjs20161209-75876-18tiu2bjs:173:8

B1966 OBD-II Trouble Code: AC Post Heater Sensor Circuit Failure

diagnostic check engine light

B1966 code definition

The B1966 trouble code detects an AC heater sensor circuit malfunction.

What the B1966 code means

The B1966 code is a generic OBD-II trouble code that notes a circuit failure in the A/C heater sensor. The heater sensor is a part of the climate control system, and works alongside the A/C evaporator. When the AC system is in use, air is passed through the evaporator before being heated. The heater sensor detects the temperature of the air, so that the air flow can be adjusted to match the desired temperature from the climate controls. If the climate control module, body control module, or powertrain control module (PCM) are unable to receive a voltage reading from the AC heater sensor, or receive an abnormal reading, then the B1966 trouble code may be stored.

What causes the B1966 code?

The most common cause of the B1966 trouble code is damaged electrical components, either in the A/C heater sensor, or in the climate control module (or connecting the two). Short wires, open or loose connectors, or blown fuses can all cause the B1966 code to be triggered. It is also fairly common for a defective AC heater sensor to cause this code. While slightly less common, climate control module failure is another possible culprit.

What are the symptoms of the B1966 code?

When the B1966 trouble code is detected, the check engine soon warning light will likely illuminate on the gauge cluster, and the AC light may flash on the climate controls. The air conditioning system will likely not operate properly, and may act erratically, or fail to produce cold air at all. In some cases, the climate control system may be entirely inoperable.

How does a mechanic diagnose the B1966 code?

The B1966 code will be diagnosed using a standard OBD-II trouble code scanner. A reputable mechanic will use the scanner to view the freeze frame data for the code, and also to check for the presence of any additional trouble codes. If the mechanic notices that numerous codes are detected, then they will need to be diagnosed in the order that they appear in. The trouble codes should then be reset, the vehicle restarted, and the B1966 code again checked for. If the code is no longer present, then an intermittent error, or an inaccurate detection are the likely faults.

If the code is still present, then the technician will begin by visually inspecting all of the electrical components, in both the climate control module, and the AC heater sensor system. Any damaged components will need to be replaced. The heater sensor itself will need to be inspected, followed by the climate control module.

After any components are repaired or replaced, the trouble codes will again be reset, the vehicle again restarted, and the code once more checked for. By doing this, the mechanic will know as soon as the issue is fixed.

Common mistakes when diagnosing the B1966 code

The most frequently made error when diagnosing this code comes from a failure to properly follow the OBD-II trouble code diagnosis protocol. Mechanics should abide by the protocol at all times, as this helps increase the chances of an efficient and accurate inspection and repair.

It is fairly common for the AC heater sensor, and sometimes even the climate control module to be unnecessarily replaced because the electrical components were not first inspected.

How serious is the B1966 code?

The B1966 trouble code will not keep a car from being drivable, or present any drivability concerns. However, the air conditioning system will likely fail to work, or work erratically, which is not only a nuisance, but can be potentially dangerous when driving in severe heat. As with all trouble codes, an inspection should be scheduled as soon as the B1966 code is detected.

What repairs can fix the B1966 code?

Possible repairs for the B1966 trouble code are:

Additional comments for consideration regarding the B1966 code

The B1966 code is a manufacturer specific trouble code. This means that the code can have varying definitions depending on the automaker. The B1966 code represents an AC heater sensor circuit failure in some cars, but can signal a very different problem in other vehicles. Mechanics should always be aware of what vehicle they are working on when diagnosing this trouble code.

Need help with a B1966 code?

YourMechanic offers certified mobile mechanics who will come to your home or office to diagnose and repair your vehicle. Get a quote and book an appointment online or speak to a service advisor at 1-800-701-6230.

The statements expressed above are only for informational purposes and should be independently verified. Please see our terms of service for more details
Icon-warranty_badge-02

Skip the repair shop, our top-rated mechanics come to you.

At your home or office

Choose from 600+ repair, maintenance & diagnostic services. Our top-rated mechanics bring all parts & tools to your location.

Fair & transparent pricing

See labor & parts costs upfront, so you can book with confidence.

12-month, 12,000-mile warranty

Our services are backed by a 12-month, 12,000-mile warranty for your peace of mind.

Get A Quote

Need Help With Your Car?

Our certified mobile mechanics make house calls in over 2,000 U.S. cities. Fast, free online quotes for your car repair.

GET A QUOTE

Post a question and get free advice from our certified mechanics.

ASK A QUESTION

More related articles

How to Buy Fuel Treatments
Adding a fuel additive to your gas tank when you fill up is one way to clean vital engine parts of deposits, improve the performance of your engine,...
Rules of the Road For Iowa Drivers
Driving on the roads requires knowledge of the rules, many of which are based on common sense and courtesy. However, even though you know the rules in...
The Traveler’s Guide to Driving in Malaysia
CraigBurrows / Shutterstock.com Malaysia is a popular destination for many tourists today. The country has amazing sights and attractions that you will want to explore....


Related questions

Q: Bad Ignition/electrical issue - takes several cranks before it starts!

Hello there, you have a few different faults going on with your 2007 Chevrolet Impala. A vehicle should not have to crank long before it starts unless there is a fault. Given the codes you have listed there are a...

Q: How do I know that my OBD system is working right?

The OBD system on your vehicle is a self-monitoring system. The Powertrain Control Module monitors and controls all of the systems and functions that regulate fuel, ignition, emissions, and engine cooling as well as having some minor control over air...

Q: Car stalling at random, could be an electrical problem?

Generally, when the car is running consistently and on all cylinders, when stalling it is often times a fuel supply issue (or in some cases indirectly related to electrical - i.e. bad connection or pulse to the fuel injectors). I...