---
product_id: 47624755
title: "30/40 AMP Relay Harness Spdt 12V Bosch Style - 4 Pack"
brand: "epauto"
price: "5045 som"
currency: KGS
in_stock: true
category: "Ep Auto"
url: https://www.desertcart.kg/products/47624755-30-40-amp-relay-harness-spdt-12v-bosch-style-4
store_origin: KG
region: Kyrgyzstan
---

# 40A max switching current Endures -40°C to 125°C 10ms ultra-fast operate time 30/40 AMP Relay Harness Spdt 12V Bosch Style - 4 Pack

**Brand:** epauto
**Price:** 5045 som
**Availability:** ✅ In Stock

## Summary

> ⚡ Upgrade your ride’s electrical game with EPAuto’s powerhouse relay harness!

## Quick Answers

- **What is this?** 30/40 AMP Relay Harness Spdt 12V Bosch Style - 4 Pack by epauto
- **How much does it cost?** 5045 som with free shipping
- **Is it available?** Yes, in stock and ready to ship
- **Where can I buy it?** [www.desertcart.kg](https://www.desertcart.kg/products/47624755-30-40-amp-relay-harness-spdt-12v-bosch-style-4)

## Best For

- epauto enthusiasts

## Why This Product

- Trusted epauto brand quality
- Free international shipping included
- Worldwide delivery with tracking
- 15-day hassle-free returns

## Key Features

- • **Built to Last:** UL-listed wires and silver contacts ensure durability and safety under extreme conditions
- • **Powerhouse Performance:** Handles up to 40 amps for heavy-duty automotive demands
- • **Lightning-Fast Response:** Operates in just 10 milliseconds to keep your systems instantly responsive
- • **Shock & Vibration Proof:** Engineered to withstand 20G functional shock and 10-55Hz vibration for rugged reliability
- • **Complete Ready-to-Install Kit:** Includes 4 relays and sockets with pre-wired leads for seamless setup

## Overview

The EPAuto 30/40 AMP Relay Harness is a UL-listed, Bosch-style SPDT relay kit designed for automotive use. It supports a maximum switching current of 40A and voltage up to 30VDC, with ultra-fast 10ms operation and robust shock and vibration resistance. This 4-pack includes heavy-duty molded relay sockets with 5 wires, silver contacts, and pigtail leads, built to perform reliably in extreme temperatures from -40°C to 125°C.

## Description

Contact Capacity: Normal switching Capacity (res.load): - NO 40A 14VDC - NC 30A 14VDC Max. switching current: 40A Max. switching voltage: 30VDC Max. switching power: 560W Characteristic Data: Initial contact resistance (at 6VDC 1A): 50mΩ Max. Operate time (at nominal volt.): 10 msec. Max. Release time (at nominal volt.): 5 msec Max. Initial insulation resistance: 100MΩ Min. (DC500V) Initial dielectric strength: - Between open contacts: AC500V, 50/60 Hz 1Min. - Between coil and contact: AC500V, 50/60 Hz 1Min. Vibration resistance: - Functional: 10 ~ 55Hz at double amplitude of 1.5 mm - Destructive: 10 ~ 55Hz at double amplitude of 1.5 mm Shock resistance: - Functional: 20G Min. - Destructive: 100G Min. Endurance (operations): - Mechanical (at 7,200 ops./h): 10,000,000 - Electrical (at 600 ops./h): 100,000 Ambient Temperature: -40°C ~ +125°C (no condensation)

## Features

- 40A/30A high switching capability.
- Heavy-duty impact molded relay socket with 5 WIRES。White (common), Black (normally closed), and Yellow (normally open).
- Package Include: 4 relays + 4 relay sockets with wires.
- Safety UL Listed 6" wires with pigtail leads for the main contact.

## Technical Specifications

| Specification | Value |
|---------------|-------|
| ASIN | B072QXDZRD |
| Best Sellers Rank | #19,779 in Automotive ( See Top 100 in Automotive ) #11 in Automotive Replacement Starter Relays |
| Brand Name | EPAuto |
| Coil Voltage | 12 volts_of_direct_current |
| Connector Type | Relay Socket |
| Contact Current Rating | 40 A |
| Contact Material | Silver |
| Contact Type | Spdt |
| Current Rating | 40 A |
| Customer Reviews | 4.7 4.7 out of 5 stars (6,853) |
| Manufacturer | EPAuto |
| Maximum Switching Current | 40 A |
| Minimum Switching Voltage | 1 volts_of_direct_current |
| Model | AE-001-2 |
| Mounting Type | Socket Mount |
| Number of Items | 4 |
| Operating Time | 0.01 seconds |
| Operation Mode | Automatic |
| Part Number | AE-001-2 |
| Specification Met | UL |
| UPC | 707129801449 |
| Unit Count | 4 Count |
| Upper Temperature Rating | 125 °C |
| Wattage | 560 watts |

## Product Details

- **Connector Type:** Relay Socket
- **Contact Material:** Silver
- **Contact Type:** Spdt
- **Current Rating:** 40 A
- **Mounting Type:** Socket Mount

## Images

![30/40 AMP Relay Harness Spdt 12V Bosch Style - 4 Pack - Image 1](https://m.media-amazon.com/images/I/61dgzu6St0L.jpg)

## Available Options

This product comes in different **Size** options.

## Questions & Answers

**Q: Where does the red wire connects to?**
A: The red wire connects to pin 87a which remains in contact with the common (pin 30, blue) when the relay isn't energized.  this is known as the "Normally closed" (NC) circuit.  Don't use it unless you want the relay to power something off when the relay activates; i.e., for most operations you leave it disconnected.

**Q: What gauge are the leads that come off the relay?**
A: The wire on these harnesses are 16AWG and are too small for powering vehicles electric fan on radiator which pulls 15-30A per fan.
Use a 30A fuse right after the battery going to the 85/86 on relay, make sure the 30 & 87 on relay have 10ga OFC primary wire.
You need 10AWG guage for 7-16ft applications, it has to be OFC/Tinned Copper, make sure it's not CCA. GS Power brand on Amazon has OFC called 100% pure copper.
Pick up yellow(12-10 guage) heatshrink butt connectors(to connect the wires properly), yellow heatshrink female spade connectors(for relay post prongs) and some yellow heatshrink ring connectors in multipack of different ring diameters(for grounding the wire to Frame bolts)
Then get heatshrink tubing 1/4" should be fine if it's 3:1 or 4:1 Wirefy is a good brand. I get the spools instead of the precut packs.
Heatshrink connectors and durable heatshrink tubing is extreamly important for automotive purpose, the weather in vehicles can corrode it and cause melting or worse.

**Q: Will these work to shut off compressors for air ride suspension on a truck**
A: As long as the total amperage draw of the compressor and any other power consuming components of the air suspension system are less then the 40 amp relay, these should work fine.

**Q: Im more of an ac instead of dc guy but u can run 24v through ur no terminal just has to have 12v to bring in the coil on the relay correct?**
A: You can apply 12VDC to the coil (usually, that means 10 -15VDC) to close the contacts of the Normally Open terminals.  When the Normally Open terminals are closed, the Normally Closed terminals are open.Once the terminals are closed, they can handle 30 amps DC.There isn't a specification for the voltage that the N/O and N/C terminals can handle... but I'm certain that they can handle 24 volts.Just don't put more than 14.4VDC across the coil.

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*Product available on Desertcart Kyrgyzstan*
*Store origin: KG*
*Last updated: 2026-09-27*