Technical

Winn Blows a Fuse

by John Winn

I spent an interesting hour in the garage with all fuses removed and all switches set to on, replacing the fuses and seeing what happened -there was a bit ofbutton-pushing too. The result may be of interest to others who built the Sierra SOHC kit, and may perhaps have some similarity to the Cortina kit loom ifPeter (Gowing) used the same principles in loom design. I guess the Sierra DOHC will have some differences due to fuel injection.

So for the Sierra SOHC I found Durite fusebox (usually mounted in engine bay) with the following

  • 10 amp - Ignition lamp (and presumably coil)

  • 10 amp - Instruments (Fuel, Temp.. Volts), oil pressure lamp

  • 10 amp - Wipers and washer

  • *20 amp - Heater fan. Rev. and Brake lights

  • 5 amp - Driver Headlight -full beam

  • 5 amp - Passenger Headlight -full beam

  • 5 amp - Driver Headlight -dip

  • 5 amp - Passenger Headlight -dip

Open Fuseblock (usually mounted in passenger footwell or glove box)

  • 10 amp - Direction and Emergency Flashers, Horn (in my case, the horn relay

  • 5 amp - Driver front and rear sidelight, Instrument lights

  • 5 amp - Passenger front and rear sidelights, Rear Number Plate lights

  • 5 amp - RearFogLamp

I expect other builders may have extended the wiring for special purposes.
My list includes:

  • 1-amp in-line clock fuse,

and a "continental" twin fuse box with

  • 8-amp fuse for a pair of horns

  • a 25 amp fuse for the radiator fan - (this was probably initially 10 amp.)

I remember Bill and Alan Brown's car blew this fuse with their heater fan on top speed and I suspect I followed their advice to uprate.(Jenny -Dave might be able to comment if the Cortina loom is anything like this fuse arrangement)

You may wonder, Jenny, what really prompted me to make this list? Well you remember my alternator hiccup in France? In the process of checking the voltage on-load one of the Ford mechanics switched the wipers straight to top speed on a dry screen they stopped at 45 degrees and only moved again when I eventually located the blown fuse and replaced it. So now I am a little better prepared for the unexpected

Best Regards,

John Winn.

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