FiveM Emergency Lights Not Working? 8 Fixes for Sirens and Lightbars
When FiveM emergency lights do not work, the cause is usually in the car files or in what else your server loads, not in FiveM itself. These are the causes we found while repairing more than 60 police and EMS cars in October 2026, in the order to check them.
| Symptom | Most likely cause | Fix |
|---|---|---|
| Works alone, dark with your other cars | Siren slot conflict | 1 |
| No lights at all, on any server | Link, bones or metas missing | 2 |
| Old pattern or still dark after you fixed the files | The client kept the old entry | 3 |
| Siren key does nothing | Class or ELS / non-ELS mismatch | 4 |
| Only the rear flashes | Headlight sequencers at 0 | 5 |
| A wall of giant glowing orbs | Corona scale too high | 6 |
| Lights, colours or tuning ignored | Data file order | 7 |
| “The siren id is too big” | Usually not the problem | 8 |
Fix 1: the car works alone but not with your other cars
GTA only keeps the last 8 bits of a siren id (id & 0xFF), so there are 256 slots. In our tests the first resource loaded keeps a slot: the police cars that stayed dark on our test server although their files were complete all shared their slot with a different Sirens entry loaded before them.
- List the slots your cars use. From your server folder, in Git Bash or Linux, this prints every slot above 20 that appears more than once:
grep -rhoP --include='*carvariations*.meta' '<sirenSettings value="\K[0-9]+' resources \ | awk '$1 % 256 > 20 {print $1 % 256}' | sort -n | uniq -c | awk '$1 > 1' - Two cars of the same resource can share one entry on purpose. Two different entries on one slot are a conflict.
- Give the car a free slot from 21 to 254: the same value in its
carcols.meta<id>and itscarvariations.meta<sirenSettings>. - Close FiveM completely (fix 3) and test again.
Fix 2: no lights at all
- The link is missing or wrong.
carvariations.metamust have<sirenSettings value="..."/>with the same value as the Sirens<id>incarcols.meta. - carcols.meta is not loaded. The manifest needs
data_file 'CARCOLS_FILE'pointing at it, and the file must be listed infiles. - The car has no siren bones. Open the model and look for
siren1,siren2… We found police cars with none: whatever the metas say, those cars cannot flash. Add bones and lenses (how). - The lenses are not bound to the bones. Each lens must be on
vehicle_lightsemissive, skinned 100% to its siren bone, with vertex alpha 0.
Fix 3: you fixed the files but nothing changed
The game keeps the first Sirens entry it loaded for a slot for the whole session. Restarting the resource, or even the server, does not replace it on a client that is still running. Close FiveM completely and reconnect after every change. We lost a test round to this ourselves: the headlight wig-wag “did not work” until a full restart, then worked.
Fix 4: the siren key does nothing
- Class. Some siren scripts only handle emergency vehicles. The one on our test server ignores any car that is not
VC_EMERGENCY. Set<vehicleClass>VC_EMERGENCY</vehicleClass>and addFLAG_EMERGENCY_SERVICEto the flags invehicles.meta. - ELS or non-ELS. An ELS car (it ships an ELS configuration file) needs its ELS resource. A non-ELS car is switched by the game or your siren script. Do not mix them on one car.
- Key. The key depends on the script: on our server, Renewed-Sirensync uses Q for the lights.
Fix 5: only the rear lights flash
The Sirens entry has its own sequencers for the car’s headlights and taillights. If leftHeadLight and rightHeadLight are 0, the front lamps never flash: that is the case in the base game’s police Stanier entry, which many add-ons copy. Give them opposite values:
<leftHeadLight><sequencer value="1431655765"/></leftHeadLight>
<rightHeadLight><sequencer value="-1431655766"/></rightHeadLight>The lamps themselves must also be tagged as headlights in the model (vertex alpha 1 and 2), which most cars already are.
Fix 6: a wall of giant glowing orbs
Coronas that grow huge at a distance come from scale set to true with a large scaleFactor. The base game’s police cars use scaleFactor 2; template packs we repaired used 10 to 100, with corona intensity up to 100. Inside <Sirens> only, bring scaleFactor back to 2 and lower an extreme corona intensity. Leave the car’s normal <Lights> alone.
Fix 7: lights, colours or tuning ignored
Load the data files in this order, so each file is read after the one it refers to:
data_file 'HANDLING_FILE' 'data/handling.meta'
data_file 'VEHICLE_METADATA_FILE' 'data/vehicles.meta'
data_file 'CARCOLS_FILE' 'data/carcols.meta'
data_file 'VEHICLE_VARIATION_FILE' 'data/carvariations.meta'Fix 8: “my siren id is too big”
A siren id with 12 digits looks wrong, but it is not a cause by itself. In our test a car with such an id lit up fine, because the game reduces it the same way in carcols.meta and carvariations.meta. Do not rewrite big ids for that reason alone: check which slot they land on (fix 1).
Test after every change
- Change one thing at a time.
- Close FiveM completely, reconnect, spawn the car and switch the lights.
- Test the car alone, then with your full resource list: a car that works alone and fails in the full list has a slot conflict.
Building new lights instead: FiveMRides Vehicle Studio BETA
When you add lights with the Vehicle Studio, the export picks a slot that no vanilla siren and no FiveMRides catalog car uses, sets the emergency class, the load order and the headlight wig-wag, and writes the slot in the resource so you can check it against your server. It cannot see the other resources on your server: if one of them already uses that slot, tell us on Discord. Emergency lights cost 1 credit per car, charged after the build is verified.
Emergency lights not working FAQ
Why are my FiveM police lights not working?
In our tests the most common cause is a siren slot conflict: another resource uses the same slot (siren id & 0xFF) and was loaded first. Then come a missing or wrong sirenSettings in carvariations.meta, a car without siren bones, a class that the siren script ignores, and a client that still holds the old Sirens entry because FiveM was not fully restarted.
What is a siren ID conflict in FiveM?
GTA only keeps the last 8 bits of a siren id, so there are 256 slots. When two resources define different Sirens entries that land on the same slot, the first one loaded keeps it and the other car shows the wrong lights or none. Give each car a slot between 21 and 254 that nothing else on your server uses.
Do I need to restart FiveM after changing carcols.meta?
Yes. The game keeps the first Sirens entry it loaded for a slot for the whole session, so restarting the resource or the server is not enough: close FiveM completely and reconnect before you judge a change.
Why do only the rear lights flash on my police car?
The Sirens entry decides whether the car's own headlights and taillights flash. If leftHeadLight and rightHeadLight have sequencer 0, as in the base game's police Stanier entry, only the taillights flash. Give the headlights opposite sequencers such as 1431655765 and -1431655766.
Which siren ids are safe to use in FiveM?
GTA uses 0 to 20 for its own cars. Pick a slot from 21 to 254 and check that no other resource on your server lands on the same value modulo 256. The number written can be larger: only id & 0xFF counts.