Relays are very much important in different car control circuits that usually operate high-power electric devices such as headlights, fans, and fuel pumps. Choosing the right relay determines vehicle performance. However, most people get confused in choosing between a 5-pin relay that can replace 4-pin socket car relays or not. In the paper, we go into differences between the 4 and 5-pin relays and analyze their compatibility in different scenarios.
Structure of 4-pin and 5-pin relays
4-pin relay structure
Control pins (85 and 86): Receive low-power signals and activate electromagnetic coils.
Output pins (30 and 87): Connect high-power devices to complete circuit closure.
5-pin relay structure
Compared to 4-pin relays, 5-pin relays have an additional pin (87a) that provides a backup current path when the relay is not activated.
Characteristics of 4-pin relay
Characteristics of 5-pin relay
- Slightly higher cost: Due to an additional contact, the price is slightly higher than that of a 4-pin relay.
The Main Differences Between 4-Pin and 5-Pin Relays
| 4-Pin Relay | 5-Pin Relay |
|---|
| 4 | 5 |
| Single-Pole Double-Throw (SPDT) |
Can 5-pin relays replace 4-pin relays?
- If the circuit only requires control of one device (i.e. single switch function), a 5-pin relay can replace a 4-pin relay, but its 87a pin will remain unused.
- If the circuit design is complex and requires a backup path, a 5-pin relay would be more suitable.
- And the electrical parameters of the 4-pin relay and 5-pin relay should be the same. For example, if 4-pin is 12v, then when choosing a 5-pin relay, 12v is also required
Is a 5-pin relay better than a 4-pin relay?
not always. The choice depends on the application requirements, with 5-pin relays being more flexible in functionality but not suitable for all scenarios.
Can a 5-pin relay function properly without using pin 87a?
Is a 5-pin relay suitable for all cars?
Suitable for most cars, but high-end or modified models may require specific specifications.
