12 V 30 A 4-Pin SPST Automotive Relay for Car and Truck Wiring

A dash switch that has to run a horn or a lamp is asked to carry more current than it wants. This four-pin SPST relay takes 12 V on the coil and switches up to 30 A through one contact pair. For car and truck wiring, alarms, locks and workshop builds.

One small relay between the switch and the load

✅ Adds a circuit cleanly Four pins and a 30 A contact let one dash switch run a horn or a lamp.

✅ Small enough to hide At about 2 by 1.5 by 3.5 cm it fits behind a dash or inside a fuse box.

✅ A spare in the toolbox A failed lamp or horn circuit does not have to wait for a parts order.

✅ Locks, alarms, boot release The same part switches door lock actuators, alarm outputs, boot release solenoids and small motors.

✅ Low current in, high out The coil takes a small control current so the switch does not carry the load itself.

Four pins and SPST are the details that decide whether this fits the job. The coil takes two pins, the contact pair takes the other two, and the contact is single-throw: it makes or breaks one circuit. A circuit that has to switch an output between two paths needs a five-pin changeover relay instead.

In use the coil is wired to the switch or the control output, and the contact pair sits in the feed to the load. That is what lets a thin dash switch or a small control board drive a horn, a lamp, a pump or a lock actuator without carrying the load current itself.

The two ratings to check before fitting are the coil voltage and the load. The coil is 12 V DC and the contact is rated 30 A, so a 24 V system or a heavier load needs a different part. The relay is CE marked and arrives one to a pack, which is worth knowing if a pair of spares is the plan.

Technical details

• Model: ZT617-12V-A-R
• Coil voltage: 12 V DC
• Contact rating: 30 A
• Contact form: SPST, one contact pair
• Pins: 4
• Body size: approx. 2.0 x 1.5 x 3.5 cm
• Certification: CE
• Pack contents: 1 relay
• Use: car and truck circuits, alarms, lamps, locks, motors

Check the coil voltage and load on your circuit, then keep a spare relay in the toolbox.

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