I guess you are not worried about the light’s name – PRNDL. You can pronounce it as “Prindle” as most people do. It stands for the acronym of ‘Park-Reverse-Neutral-Drive-Low’. Well, it represents the sequence of the shift pattern on automatic vehicles. Sometimes the PRNDL light gets some issues and leave a question, “Why is my PRNDL light not lighting up?”
Some common reasons are malfunctioning TRS circuits, faulty TCM or PCM, damaged wires, defective valves, etc. Sometimes, a blown fuse, faulty relay, or a burnt-out bulb can also prevent the light from lighting up.
In this article, I will explain all possible reasons and ways to solve the non-illumination of PRNDL light. You can diagnose and fix them by following my instructions. Plus, I will add some instructions to keep the light active without having those issues.
A Brief to PRNDL System & Its Components
Before you learn about the problems, it will be helpful to learn about the PRNDL system. It refers to the automatic transmission gear selector. Here is the definition of each letter in the acronym “PRNDL” (1,2):
| P for Park | In this mode, transmission is locked to prevent the car from moving. |
| R for Reverse | Reverse mode allows the vehicle to move backward. |
| N for Neutral | The transmission is disengaged (the engine runs but doesn’t drive the wheels). |
| D for Drive | The transmission automatically shifts through gears as you accelerate and decelerate. |
| L for Low | In Low mode, the transmission is held in its lowest gear. |
Besides the above modes, some cars have an ‘S’ or Sport mode. It keeps the transmission in each gear longer before upshifting to maximize acceleration (3).
PRNDL lights are the lights on your car’s dashboard that are the main parts of this system. If your PRNDL light is not lighting up, it may indicate a problem with any of these modes or components.
Causes & Their Solutions of PRNDL Light Not Lighting Up
When you see your vehicle is not functioning properly or any of the above modes is not working, the PRNDL light may not work. Aside from these, below are the reasons for the problem I am talking about:
Reason: 1 – Burned Out Bulbs
Well, a common reason for the PRNDL not lighting up is a burned-out bulb. Like other bulbs, the bulb that illuminates the PRNDL can burn out. Definitely, no burned-out bulb will light even if it has power flow, or the rest of the dashboard lights work.
Solutions
Chill! You need to replace the bulb. To replace the PRNDL burned-out bulb, access the bulb by removing the necessary components. In this case, you must remove the plastic trim piece on the center console. Then, unclip the wire harness and remove the trim (4).
Disconnect the bulb from the PRNDL bezel. Now, it’s time to replace the bulb. After replacing the bulb, you can reassemble the components in reverse order. I suggest you read the vehicle’s manual before following the whole process.
Reason: 2 – Damaged Wiring
For different reasons, damaged wiring may affect the PRNDL light. They can be a malfunctioning transmission range sensor, faulty wiring, or a bad shift linkage (5). Besides, damaged, burnt, shorted, disconnected, or corroded wiring and connectors can also cause issues with the PRNDL light (6). These wires can disrupt the electrical flow and plunge the PRNDL lights into darkness.
Solutions
First, check the wiring for any wire shortage, incorrect adjustments, and excessive mechanical wear of control linkages or cables. If you find any of these, change the cables or adjust them properly (like tightening the loosened wire). Usually, a longer length of wire encounters more resistance and causes more energy loss. So, use a wire with the correct length.
Reason: 3 – Faulty Transmission Range Sensor
The Transmission Range Sensor (also known as TRS) informs the Engine Control Module (ECM) or Transmission Control Module (TCM) about the shift lever’s position. It may send incorrect signals when it is faulty. Also, the “service engine soon” light on the dashboard may remain lit if the sensor malfunctions (7).
However, a faulty TRS circuit may prevent the PRNDL light from lighting up. It will often indicate a diagnostic trouble code P0705 (5). This malfunction can cause the vehicle not to start. It is because some cars have a neutral safety switch that only allows the vehicle to start in the Park/Neutral position (8).
Solutions
If you get the error P0705 code or your vehicle does not start as the PRNDL doesn’t light up, you must replace the faulty TRS circuit. Call a mechanic to troubleshoot the error, as it involves working with the vehicle’s transmission system.
Reason: 4 – Faulty Relay or Fuse
Relays and fuses regulate the electrical supply to the PRNDL lights. When they malfunction or blow unexpectedly, they may disrupt this supply. As a result, you may have the PRNDL light failure.
Common faults of relays include poor product quality, improper use, and poor maintenance. They can lead to various failures (9). Then, a faulty relay can cause a completely open electrical circuit inside the neutral safety switch. It will cause issues with the PRNDL light.
Solutions
You must check and replace the malfunctioning relay or blown fuse to keep the PRNDL light turned on. To replace a relay or fuse, you can read the user manual or get assistance from a professional.
Reason: 5 – Malfunctioning Dash Cluster
The Dash Cluster houses the PRNDL and other essential gauges and indicators. However, a malfunctioning cluster can affect the PRNDL’s operation. Hence, it may indicate a problem with the entire Dash Cluster or just the PRNDL component.
Several issues can cause dash cluster malfunctioning. For instance, a faulty component like a voltage regulator or speed sensor can cause inaccurate readings. You may also experience inconsistent behavior of the dashboard gauges (11).
Solutions
If the Dash Cluster is malfunctioning, you must repair or replace it. However, repairing or replacing the cluster is a professional mechanic’s job. So, it will be hard to repair or replace it by yourself as the components are a bit complicated.
Reason: 6 – Switch Malfunction
The PRNDL switch activates the lights. But it can become faulty over time. It may lead to hard shifting due to confusion about the selected gear (10).
Solutions
Diagnose the switch to see if it is okay to activate the lights. If not, I suggest you replace it soon.
How Can I Prevent PRNDL Light in My Car from Failures?
Indeed, you can prevent light malfunction before you experience it. Likewise, some tips regarding this from me are:
- Check the PRNDL light’s condition regularly.
- Avoid using excessive force when shifting gears.
- Ensure the proper adjustment and functioning of the shift linkage.
- Maintain the health of the Transmission Range Sensor. Also, ensure it is not defective or misadjusted.
- Regularly check and maintain the quality of the transmission fluid. Low or contaminated fluid can cause problems in the valve body that shift gears.
- Ensure the proper functioning of the Transmission Control Module (TCM) or Engine Control Module (ECM).
- Maintaining the internal mode switch in good condition to prevent the PRNDL display from stopping working and leading to hard shifting.
- Do not use low-quality components, like bulbs and wiring, as they may be damaged soon.
- Clean your vehicle regularly to prevent dirt and dust accumulation in the PRNDL area.
Final Words
I always welcome my readers – like you who need or are curious to learn new things. Like other discussions on this site, this one is important if your car has PRNDL lights. However, have you read the explanation of this question thoroughly?
Why is my PRNDL light not lighting up?
If you read the whole article, I hope you have learned about the reasons. Now, you can sort out what actually happened with your car’s PRNDL lights. Before troubleshooting, check everything related to the PRNDL system like its components and functions. Then, you can follow my instructions.
Let me recall one thing: from light and switch to others can be the culprit to PRNDL light failure. So, please keep your eyes open and maintain the car and its components, like the lights.
That’s all for today! Got it?
Thanks for reading this guide.
