R22 fuse on back of firewall?
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Join Date: Oct 2011
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R22 fuse on back of firewall?
What is the purpose of the fuse located on the engine side of the firewall on the R22 - low, near gascolator. You can just about see it in this photo - at the top on the right, a vertically mounted clear glass fuse: 
Many thanks in advance for any help,
Jay
Many thanks in advance for any help,
Jay
Join Date: Aug 2011
Location: Ventura Ca U.S.A.
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I see a diode on a relay-As the relay deenergizes the break down of the magnetic field causes a voltage spike, the deode shunts the spike to the ground side of the coil.
Made to save the fine electrinics from harm.
Made to save the fine electrinics from harm.
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The 3 AMP fuse mounted on the vertical firewall is the Battery Relay Bypass Circuit fuse, used to protect the clock and also the Dual Tacho which is hard wired to the battery through the Clutch Switch.
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Hillberg, the spare fuse that you describe is next to the warning light test switches under the cowl on the right hand side and that one is for the clutch. The 'relay' is actually part of the oil gauges system, the oil pressure sensor.
As Powerlimited says, the fuse pictured is a fuse to protect the by-pass wire that runs the clock and the RPM gauges. The RPM gauges only get power though when the clutch is engaged. The wire is referred to in the POH/RFM on page 7-12, Systems.
To know if the fuse is working or intact, check the clock prior to start. If it is not working, then the fuse is blown.
As Powerlimited says, the fuse pictured is a fuse to protect the by-pass wire that runs the clock and the RPM gauges. The RPM gauges only get power though when the clutch is engaged. The wire is referred to in the POH/RFM on page 7-12, Systems.
To know if the fuse is working or intact, check the clock prior to start. If it is not working, then the fuse is blown.
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Last R-22 I worked on that fuse for the tach/clock was in the instrament pnl. But that was some time ago, when the battery was in the nose 
& not the left rear, My have things change. 
& not the left rear, My have things change.
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by-pass wire that runs the clock
