Talk Morgan Forums Morgan Sports Cars Maintenance & Servicing Renewing the twin aero horns

Essentially its this Graham.



Shown here is a simple on/off relay but a 5 pin changeover type as usually fitted by MMC works equally well - just ignore the 87a contact. Important you use a diode suppressed one as factory fitted though to avoid pulses that may damage ECU.

The device are the horns in this case and the ground trigger source the horn push. BTW might be worth taking your steering wheel off to see reason for difficult operation. I found no need for extra wiring simply using the two horn feeds, both light green/white in wiring loom, to connect to pin 86 (coil live) and pin 30 (main power to relay). These feeds are already fused although you may need to uprate fuse. The purple/black wire is ground switched feed from horn push so it goes to pin 85. Ensure second one in loom (present even if only one OE horn fitted) is isolated.

Finally in car electrics as elsewhere, the KISS principle rules