Horn Relay Board Circuit Diagram and Layout

This page has the circuit diagram and board layout for our horn relay board.

Circuit diagram:

Operation

A six way input connector is fitted, although normally only two pins [C & D] are used. The extra four pins are provided to add to the board’s versatility.

( ) indicates that the connection is not normally used

[ ] indicates alternative function which may be obtained by altering the board.

Pin	Purpose	Alternative Use
A	(Battery negative)
B	RL3	[RL4]
C	RL3
D	RL2 and RL1	[RL2]
E	RL2 and RL1	[RL1]
F	(Battery positive)

RL1 and RL2 are operated via a single wire to either input pin E or pin D. Two pins are used so it is possible to split operation and have the relays operating separately (not a feature of the standard board).

Connecting one of these pins to B- (battery -ve) operates RL1 and connecting it to B+ (Battery +ve) operates RL2.

Connecting pin C or B to Battery – operates RL3.

 

Board layout – Underside: Note location of link K in red.

Board layout – Topside: