All E450 chassis, both "cutaways" and those destined to live beneath full Econoline van bodies, share major sections of the wiring harness because it's easier and/or cheaper for the manufacturer (Ford) to do it that way, both for ease of assembly and for spare parts logistics. Consequently, things like a rear defogger that might be present on a full van body go unused on a cutaway chassis destined for use as a C class platform.
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