Example embodiments described herein relate to a modular telematics control unit (TCU) with directional Bluetooth Low Energy (BLE) and techniques for using the modular TCU with directional BLE. A modular TCU may include a housing configured to couple to a vehicle and a set of Bluetooth Low Energy (BLE) radios. Each BLE radio is coupled to a corresponding BLE antenna configured for omnidirectional operation. The set of BLE radios and BLE antennas are located within the housing. The modular TCU also includes a heat sink located within the housing and positioned proximate the BLE antennas such that the heat sink limits operation for each BLE antenna to a particular direction extending away from the housing. In some instances, a vehicle computing system may use BLE to detect a device and perform operations based on the location of the device relative to the vehicle.