2013 Ram 1500 Cooling Fan Relay Location

Where the fan relay is located

Open the hood and look on the driver side of the engine compartment, beside the battery. The black plastic box there is the power distribution center, which holds the high-current fuses and relays for the engine and body circuits. Release the lid latches and turn the lid over. The diagram printed or molded on its underside identifies each position, including the radiator or cooling fan relay and the fuse that protects the fan feed. Go by that label rather than a generic photo, because the layout of the cavities varies with build options and production date.

Some configurations do not use a conventional replaceable relay to switch the fan. Instead, the engine computer may command a fan control module or solid-state driver mounted at the fan shroud, and the distribution center may contain only a fuse for the fan circuit. If the lid label shows no fan relay, this is the likely explanation. Do not pull unrelated relays at random hoping to find it.

How the cooling fan circuit works

A relay-controlled fan circuit has two halves. The control side is a low-current circuit. The powertrain control module reads coolant temperature, air conditioning demand and vehicle speed, then energizes the relay coil when cooling airflow is needed. The load side carries the heavy current. When the coil is energized, the relay contacts close and send battery power through a high-amperage fuse to the fan motor. The motor then returns that current through its ground connection to the body or frame.

Because the fan motor draws far more current than most accessories, the fuse rating on its feed is high and every connection in the path matters. A small amount of corrosion or looseness at a terminal creates a voltage drop. That drop slows the fan, heats the connector and can burn the relay contacts over time. With the engine running, the alternator's charging output holds system voltage around 13.5 to 14.5 volts. A healthy circuit delivers close to that same voltage to the fan connector when the fan is commanded on.

What changes the answer

The 2013 Ram 1500 was offered with a 3.6-liter V6, a 4.7-liter V8 and a 5.7-liter V8. Depending on engine, towing equipment and other options, a given truck may rely on an electric fan, an engine-driven fan with a clutch, or a combination. Look behind the radiator before buying parts. A fan mounted on the front of the engine and turned by the belt is not controlled by a relay, so a relay cannot explain its behavior. Only an electric fan with a wiring connector at its motor or shroud uses the relay or control-module circuit described here.

The control strategy also varies. Some setups use a single-speed relay, some use separate relays for low and high speed, and some use a pulse-width-modulated module that varies fan speed without a traditional relay. The wiring diagram for your specific VIN shows which design you have. Everything in this circuit runs on the conventional 12-volt starter battery. Standard production 2013 Ram 1500 trucks have no high-voltage traction battery feeding the cooling fan. If you are working on a different vehicle with orange high-voltage cabling, this procedure does not apply, and that system needs its own manufacturer isolation steps.

How to check and replace the relay safely

Shut the engine off, remove the key and let the engine cool. An electric fan can start without warning while the engine is hot, so keep hands, tools and loose clothing away from the blades. Simply swapping a relay with the key off is low risk. Before unplugging the fan connector or doing any wiring repair, disconnect the negative cable at the battery terminals and position it so it cannot touch the post. Disconnecting the battery may clear radio presets and some learned settings, which is normal.

Start with the fan fuse and test it with a test light or meter, because a fuse can look intact and still be open. Next, swap the fan relay with an identical relay from the same box. Use one with the same part number that serves a non-critical circuit. If the fan now works, the original relay was faulty. With the engine running, turning on the air conditioning often prompts the computer to command the fan, which makes a convenient test condition. While the fan is commanded, measure voltage at its connector and compare it with battery voltage. As a rough guide, more than about half a volt lost on either the feed or the ground side points to a resistance problem in the wiring or connections.

A fan that keeps running long after shutdown often has a relay with welded contacts or a control circuit stuck on. That can create a parasitic draw heavy enough to flatten the battery overnight. Pull the relay. If the fan stops, the relay or its control signal is at fault. If it keeps running with the relay removed, power is reaching the fan by another path, such as chafed wiring. When replacing parts, match the part number printed on the relay housing and install a fuse of exactly the specified rating. Never fit a larger fuse to stop repeated blowing.

Limitations and the next step

This guide deliberately does not list a cavity number or fuse rating, because both vary with production date and options. The label on the distribution center lid and the factory wiring diagram for your VIN are the reliable references. A dealer parts or service counter can confirm them from the VIN.

Get professional diagnosis if the fuse and relay test good but the fan still does not run, if the fuse keeps blowing, or if you find melted terminals in the distribution center. A scan tool with bidirectional control can command the fan directly and read cooling-related fault codes. That separates a computer or sensor problem from a wiring or motor fault. If the temperature gauge climbs toward hot, stop driving and let the engine cool rather than continuing while you troubleshoot.