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FLASHER RELAYS
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United Pacific 17 LED Dual Function Watermelon Double Face Light | 37477
Brand:
United Pacific
SKU:
37477
Price:
$60.59
Grote Rear Marker High Mount STT/Left Hand/RD | 01-5445-75
Brand:
Grote
SKU:
01-5445-75GR0
Price:
$238.53
Federal Signal Amber LED Strobe Light | 252650-02SC
Brand:
Federal Signal
SKU:
252650-02SC
Price:
$262.99
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Flasher Relays For Peterbilt Trucks
Flasher relays control the timing and cycling of turn signals and hazard lights on a Peterbilt truck. A failed flasher relay results in turn signals that don't flash, flash too fast, or don't illuminate at all — conditions that are both a safety hazard and a DOT inspection violation. We carry replacement flasher relays and electronic turn signal modules compatible with Peterbilt trucks across model years, including both thermal and solid-state designs.
Frequently asked questions about flasher relays
Why do my turn signals flash faster than normal on a Peterbilt?
Rapid or hyper-flashing is almost always caused by a burned-out bulb in the turn signal circuit. Traditional thermal flasher relays are calibrated for a specific load — when a bulb fails and reduces the circuit's current draw, the flasher cycles faster. Check all turn signal bulbs on the affected side, including trailer markers if connected, before replacing the flasher relay. On trucks that have been converted to LED lighting, an electronic load-equalizing flasher relay is required to prevent hyper-flash.
What's the difference between a thermal flasher and an electronic flasher relay?
A thermal flasher uses a bimetallic strip that heats and cools to create the flash cycle — its timing is affected by temperature and bulb load. An electronic flasher uses a solid-state timer circuit for consistent, temperature-independent flash rate and is generally more reliable over time. Electronic flashers are also compatible with LED lighting without the hyper-flash problem that thermal units exhibit with reduced-load LED circuits.
Where is the flasher relay located on a Peterbilt truck?
On most Peterbilt models, the flasher relay is located in the main fuse and relay panel, typically found in the cab behind the driver's side kick panel or dash access panel. Some configurations place it in an underhood power distribution center. Consult your model-specific wiring diagram to confirm the relay location and socket type before purchasing a replacement.