It monitors, it does not control. The sensor logs the actual trailer temperature and alerts when it drifts out of range, but it does not change the reefer set point. You get an early warning to act before the load is lost, plus a record of what the trailer actually held.
GPS Tracking with Temperature Sensors for Reefer Trailers
Protect temperature-sensitive cargo on every route
A GPS tracker with a temperature sensor records where a reefer trailer is and how cold the cargo is, minute by minute. Top Tracking System puts that on one dashboard with your GPS fleet tracking and ELD, sends an alert the moment temperature drifts out of range, and keeps the trip log you need for FSMA and a rejected-load claim.
What Top Tracking System temperature sensors do
Live location
Every reefer on one map in real time, so dispatch can reroute around delays and give receivers accurate ETAs.
Continuous temperature logging
A wireless probe reads the trailer air or return-air temperature every few minutes and stores it, so you have a full record, not spot checks.
Out-of-range alerts
Set a high and low limit per load and get a text the moment the trailer drifts past it, while there is still time to fix the reefer.
Geofencing alerts
Draw a zone around a DC, cross-dock, or customer and get an alert when a trailer arrives or leaves, day or night.
Trip and temperature history
Replay any run with location and temperature side by side, including door-open events, to show a receiver the load stayed in spec.
Speed alerts
Get flagged when a truck exceeds a set limit or the posted road speed, data a CSA review and a crash lawyer both check.
Maintenance reminders
Schedule tractor and reefer-unit service by engine hours or odometer, so a PM is never missed.
How temperature monitoring works, in 3 steps
Mount the GPS, place the probes, then watch temperature and location from the same dashboard.
- 01
Install the sensors
The GPS unit mounts on the tractor and wireless probes go in the trailer, one per zone for multi-temp loads.
- 02
Data transmission
Location and temperature readings go to the cloud over cellular, and store on the device through any dead zone.
- 03
Fleet monitoring
The dashboard shows live temperature and location per trailer, sends out-of-range and door-open alerts, and exports the trip temperature report for a shipper or a claim.
Why fleets choose Top Tracking System for cold chain monitoring
We are a small US-based company built around trucking technology. The difference shows up in 3 places: the support you reach, the contract you sign, and the number of vendors you manage.
Focused on trucking since 2016. Temperature and fuel sensors, GPS, ELD, and cameras are all we build.

One platform, one bill. Temperature sensors, GPS, ELD, and cameras run on the same dashboard, not 3 or 4 logins.

Support you can reach. Phone, email, and WhatsApp from a US-based team, on a month-to-month plan.

Temperature sensor questions carriers ask before they buy
Straight answers on reefer control vs monitoring, probe placement, rejected loads, FSMA, and adding sensors to trailers you already track.
Ready to protect every reefer load?
Talk with our team about temperature probes, GPS trailer units, and the trip logs shippers ask for.
