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Ron Kwas · Jul 6th, 2020, 18:50

HWK;

Late Amazons had a Batt power (Brn) wire in the harness to the rear, (Ref: 123GT Wiring Diagram: https://www.sw-em.com/123GT-Wiring-Diagram_US.jpg Item 60) but it was only an 18ga/1,0mm2, intended for the minimal current of trunk/boot light only. This wire is not suitable for a Rear Window Defroster.

A RWD of any effectiveness (Resistance conductor as the heated glass type, or warmed air, which I prefer, see reason below!) should be around 100W, and that requires a new wire to be routed. I recommend gauge of that should be 12ga/4mm2 wire (AND also that this elec load not be installed before vehicle gets an uprated output Charging Sys, like an [>55A] Alternator), because pulling 100W (=8.5A) out of elec sys when Chg Sys is powered by a 30A oe Gen means that when that load is in use, Batt will not be being charged, in fact, likely being discharged because it needs to contribute power.

Ref: https://www.sw-em.com/accessorize.ht...dow_Defrosters

Cheers

Jul 6th, 2020, 18:50	#7
Ron Kwas Premier Member Last Online: Today 17:04 Join Date: Jul 2007 Location: Connecticut, USA	HWK; Late Amazons had a Batt power (Brn) wire in the harness to the rear, (Ref: 123GT Wiring Diagram: https://www.sw-em.com/123GT-Wiring-Diagram_US.jpg Item 60) but it was only an 18ga/1,0mm2, intended for the minimal current of trunk/boot light only. This wire is not suitable for a Rear Window Defroster. A RWD of any effectiveness (Resistance conductor as the heated glass type, or warmed air, which I prefer, see reason below!) should be around 100W, and that requires a new wire to be routed. I recommend gauge of that should be 12ga/4mm2 wire (AND also that this elec load not be installed before vehicle gets an uprated output Charging Sys, like an [>55A] Alternator), because pulling 100W (=8.5A) out of elec sys when Chg Sys is powered by a 30A oe Gen means that when that load is in use, Batt will not be being charged, in fact, likely being discharged because it needs to contribute power. Ref: https://www.sw-em.com/accessorize.ht...dow_Defrosters Cheers Last edited by Ron Kwas; Jul 6th, 2020 at 19:54.