Alloy Safety Interlocking Engine Start Switch

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• Alloy Safety Interlocking Engine Start Switch
  Bob Smith
• Please use this information and associated
  photographs in good faith.
• The Author does not guarantee the accuracy of
  the information and is not liable for use of said
  information.
• Ownership remains the property of the Author.
  The information and associated photographs must
  not be copied, profited by or used for commercial
  gain.

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Wiring schematic
30
Start button With LED
87

-
85
RLA Coil
86
RLA 2
1
9
5
To Starter (to white/red wire)
30A inline fuse
4
12
8
Permanent ve (to red wire)
14
RLA Coil
13
Oil pressure Switch ve (to brown/white wire)
RLA 1
Ignition ve (to white wire)
3
Parts list Switch Momentary starter
Pushbutton engraved alloy with blue LED UR
Motoring www.ur-motoring.co.uk RLA 1
5A 12Vdc DPDT Maplin p/n JG66W RLA 2
40A 12Vdc SPST Maplin p/n AR32K
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Instructions Based on 99 Chimaera Use 18 gauge
wire throughout. Access required to top of dash
(can be achieved with only the two passenger side
nuts removed but be careful not to over strain
things). I chose to fit the switch in place of
the rear guard fog light switch so I also needed
access to the radio console. The push button
switch will need to be ordered with an additional
power switch fitted UR Motoring can supply. I
moulded an additional aluminium outer ring for
the switch so that it would better match the
standard switchgear. This system employs an
interlocking relay to prevent accidental starting
when the engine is running and to maintain
electrical power once the start process is
underway. This utilises the ve signal from the
oil pressure switch to let the system know the
engine is not running. Once the start process
begins the signal from the oil pressure switch is
overridden with a self latching switch within RLA
1. That way even if oil pressure is generated
whilst cranking the engine the start system stays
live. Once the engine is running the signal from
the oil pressure switch prevents accidental
operation. Connecting to existing wiring The oil
switch signal wire is brown with a white stripe.
This wire is within a loom that enters the upper
dash near centre then feeds towards the off-side.
There is a spare brown/white wire lying
alongside this loom probably there for a remote
oil light and is unused on my Chimaera. This
wire terminates with a female miniature spade
connector. Use this for the oil pressure
switch signal. All other connections are made in
the steering wheel cowl. Link into the ignition
loom on the nearside of the steering column. Wire
colour codes Ignition ve White Permanent
ve Red Starter White/Red Earth to chassis