40 merc dash harness question/heater switch

L

LRS30

Junior Member
I started with a Bob Drake complete wiring harness, headlights, engine,tailight harness, all correct lengths, color coded, great instructions! But, yes there is a but my Merc is equipped with a heater and on the dash harness and diagram there is no provisions for a heater. So here is my question, has anybody ran into this problem, did I order the wrong harness? Everything else lined up and hooked up perfect! If you have ran into this how did you remedy it? Tap off cig. Lighter power? Does anybody have a wiring diagram with a heater on it? I know it's a lot of questions but I really don't wanna hack up anything if I don't have too.
 
Mercury was probably like Ford in that heaters were a dealer-installed accessory. Here's a link to instructions for installing a Ford authorized hot water heater in a 1940 Ford:http://www.flatheadv8.org/91A-18457 Heater.pdf As you see, extra wiring was required to route the power from the ignition switch through the heater switch to the heater. Hope this helps.
 
AWESOME! Thanks for the info! I tried chasing the old harness out but it was a rats nest! No way of ever telling what went where!
 
Heater wiring harness was a seperate harness. Check with Chris Olsen at Class Tech in Bend, Oregon. He makes most of the harnesses for the venders. He should be able to supply you with one.
 
The heater switch should mount hanging down off the Lt. under side of the dash near the drivers side door. Should already have a hole in the under side of the dash.
 
See if any of these help. On any of the older Fords (prior to a modern style ignition switch) the power to the heater switch should come from the fuse/CB panel.
 

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jimTN said:
JSeery, could you please post a larger printable version of the 46-9 heater wiring diagram.
Click to expand...

Looks like 4dford did (well for the 39-40, which should be more appropriate). 6v vs 12v shouldn't an issue except if the original heater fan is 6v I would use a voltage reducer, but it would wire up the same.
 
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