Chevy Trax Cooling Fan Relay Location

Where the cooling fan relay is located

On a Trax that uses conventional fan relays, they sit in the underhood fuse block in the engine compartment, next to the 12-volt battery. Lift the fuse block cover and find the legend, which is printed on the underside of the cover or listed in the owner's manual. It names or numbers each relay and fuse position. Depending on model year and equipment, you may find more than one fan-related relay. Some systems use separate relays to produce low and high fan speeds.

Don't rely on a photo of another vehicle or another Trax generation. The layout inside the block, the number of relays, and even whether the fan uses a conventional relay at all can all differ. The legend on your own vehicle is the authoritative guide to which socket controls the fan.

How the fan circuit is switched

The engine control module decides when the fan should run. Its inputs include engine coolant temperature and air conditioning refrigerant pressure. The module does not power the fan motor directly. It controls the relay's coil, typically by completing the coil's ground circuit. When the coil is energized, the relay's internal contacts close and connect a fused battery feed to the fan motor.

The relay exists because the fan motor draws far more current than a module output can safely carry. For the same reason, the fan circuit has its own high-amperage fuse. It also explains why a burned relay terminal, a corroded socket or a weak ground connection can stop the fan even when the module is commanding it correctly. On two-speed systems, the relays route current so the motor gets reduced voltage at low speed and full voltage at high speed.

What changes the answer for your Trax

The first-generation Trax and the redesigned Trax introduced for the 2024 model year use different engines and different underhood layouts, so relay positions don't carry over between them. Some modern GM fan designs also use an electronic fan control module that varies fan speed itself instead of switching it through relays. If your fuse block legend shows no fan relay, your fan is probably module-controlled. In that case, swapping a relay will not change anything, and diagnosis moves to the module, its wiring and the fan motor.

Operating conditions matter too. With a cold engine and the air conditioning off, it is normal for the fan to stay off. Turning on the A/C usually makes the module request the fan. A hot engine may keep the fan running briefly after shutdown. A fan that keeps running long after the ignition is off, especially once the engine has cooled, points to relay contacts stuck closed. That condition creates a parasitic draw that can flatten the battery overnight.

Safe isolation before you work on the fan circuit

The cooling fan can start without warning while the ignition is on or the engine is hot, so keep hands, tools and clothing away from the blades. Switch the ignition off, keep the key or fob away from the vehicle, and let the engine cool. Pulling or swapping a relay with the ignition off needs no further isolation. Before you probe or repair wiring, disconnect the negative battery terminal first and reconnect it last. Expect some settings, such as radio presets, to reset.

The gasoline Trax runs on a conventional 12-volt system powered by its starter battery. It has no high-voltage traction battery and no orange high-voltage cabling, so disconnecting the 12-volt negative cable is the correct isolation step. This applies only to this kind of vehicle. Hybrids and electric vehicles have a separate high-voltage system that requires its own manufacturer-specified shutdown procedure.

Checking the relay, fuse and power supply

Start by measuring system voltage at the battery terminals. A healthy battery at rest usually reads about 12.4 to 12.6 volts. With the engine running, roughly 13.5 to 14.7 volts shows normal charging output. Low voltage can make relays chatter and fans run weakly. Next, inspect the fan fuse in the same block. Replace a blown fuse only with one of the fuse rating shown on the legend, never a larger one. A fuse that blows again points to a short or a seized fan motor.

A quick swap test is often the fastest check. If another relay in the block has exactly the same part number and terminal layout, and it serves a non-essential circuit, swap the two temporarily. If the fan behavior changes, the original relay is faulty. You can also start the engine and switch on the A/C while a helper rests a finger on the relay to feel for a click. Keep well clear of the fan while you do this.

To bench test a removed relay, use the diagram printed on its case. Many relays use the common 85 and 86 numbering for the coil and 30 and 87 for the switched contacts, but confirm this before connecting anything. Check that the coil has resistance rather than an open circuit. Then energize the coil with a fused 12-volt jumper and confirm continuity across the contacts. In the vehicle, use the wiring diagram to identify the socket's feed terminal and check it for battery voltage. A voltage drop test across the connections while the fan runs will reveal hidden resistance. More than a few tenths of a volt across a single connection deserves attention.

Limitations and next step

Relay testing only proves the relay and its power feed. If the relay and fuse are good but the fan is never commanded, the cause may be the coolant temperature sensor, the engine control module, the control wiring or the fan motor itself. A scan tool with output controls can command the fan directly. That is the most reliable way to tell a command problem from a power-side fault. Exact terminal numbers and wire colors depend on model year, so use the wiring diagram for your specific vehicle.

If the temperature gauge climbs toward hot, stop driving, because overheating can seriously damage the engine. Get professional help if the fan fuse keeps blowing, if you find a melted relay socket, or if your Trax uses a fan control module instead of relays. Those faults usually need dealer-level diagnosis.