The CHMSL fuse is the fuse in the circuit of the Center High Mounted Stop Light - the light that's located on the rear window. And whenever you need to check or replace this fuse, you should look for it in the interior fuse box, most often, on the left of the dashboard.
Fuse problems highlights
- Level of urgency:medium
- DIY inspection:possible
- DIY repairs:possible
- Can you drive?yes, if it starts
- Price of repairs:$0 - $50
- Ifignored:certainequipment will not be working at all
- Ways to fix:test the fuses, replace the blown fuse
What's the CHMSL fuse?
In most cases, you will find this acronym when studying the fuse map of your General Motors vehicle. This is the special fuse that is integrated into the circuit of the stop lamp mounted high in the interior of your car - somewhere in the rear window area. This lamp is a standard feature for almost all vehicles that are aimed at improving the safety of your driving.
When some car follows your vehicle closely, its driver may not see the main stop lights. But they will obviously see the center high-mounted light in the rear window of your vehicle.
So, when this lamp doesn't work, one of the most common reasons for this issue is the burnt fuse - exactly the CHMSL fuse.
In most cases, this is the 10-amp fuse that may burn just because of its age or because of sharp spikes in voltage, or any other problems in the electric circuit of your vehicle.
Where is the CHMSL fuse located?
This highly depends on your vehicle model and year, but you should start searching from the interior fuse box located on the left side of the front panel. You may access this fuse box by detaching a small plastic cover on the left side of the front panel. In most vehicles, the map for this box is located right on the back of this plastic cover.
The CHMSL fuse is just a standard 10-amper fuse and you can take it off with the universal fuse removing tool or even with your hands.
How to check and replace the blown CHMSL fuse?
If it's burnt, the extra stop light will not be working. This is the only sign that shows you something is wrong with this system. But you should still check it because the light may not be working due to wiring issues or burnt lamps.
So, the easiest way to check the CHMSL fuse is the following:
- locate the fuse in the left-side interior fuse box in your GM vehicle;
- take this fuse out and check if it has some signs of burning in it;
- take another 10-amp fuse and insert it in this slot - you may even take another fuse from this box if you don't have any spare fuses;
- now turn on the ignition and ask someone to press the brake pedal;
- look at the rear stop light that is mounted in the area of the rear window;
- if it's working, the fuse is to blame, but if it's still not working, find another reason for this problem.
Once you are sure the problem was exactly because of the fuse, you may replace it. But within several weeks, pay attention to how the brake light works. Fuses don't usually blow just for fun - there was some problem that made it blow.
If you have the multimeter, it would be nice to make some measurements in the circuit to make sure that everything is fine.
Why does my CHMSL fuse keep blowing?
If the stop light fuse keeps burning, there is a problem in the circuit. In most cases, the issue should be with the wiring. Maybe, some connection is unstable and when it goes on and off, the fuse may burn. Also, one more possible reason is the problem with the voltage regulator in your alternator.
If the alternator sends the wrong voltage to the vehicle's system, some fuses may burn regularly. Check the alternator and how it works before it's too late. The wrong voltage regulator may burn not only fuses but some more important and expensive units in your car.
In conclusion, your CHMSL fuse is in charge of the center high-mounted stop light and this is the only job this fuse does in your car. Change it if the stop light is not working completely.
About the authors
The CarAraC research team is composed of seasoned auto mechanics and automotive industry professionals, including individuals with advanced degrees and certifications in their field. Our team members boast prestigious credentials, reflecting their extensive knowledge and skills. These qualifications include: IMI: Institute of the Motor Industry, ASE-Certified Master Automobile Technicians; Coventry University, Graduate of MA in Automotive Journalism; Politecnico di Torino, Italy, MS Automotive Engineering; Ss. Cyril and Methodius University in Skopje, Mechanical University in Skopje; TOC Automotive College; DHA Suffa University, Department of Mechanical Engineering
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