headlight switch wiring

[EScanlon]

Yeah, that makes sense at first blush, but think about it... The same current coming OUT of the high beam on the thicker wire had to be supplied INTO the bulb through the thinner wire.

I'm talking about after they have split for each side. This is right at the connector leading through the fender walls and into the buckets.

I'll snap some pics tomorrow if I get a chance.

It wasn't intended to be an easy question... :classic:

You forgot to "carry the one".

You have current being "supplied INTO" EACH " bulb through the thinner wire" then "coming OUT of" EACH "of the high beamS onTO the thicker wire" where BOTH High Beams then merged to return to the combination switch.

Without the allegory, simply put, you may have a smaller current going into each bulb independently of each other, but when they join to return to the combination switch, you now have TWO small currents (making one bigger one) returning at the same time.

Make sense now?

HTH

E

[Captain Obvious]

you may have a smaller current going into each bulb independently of each other, but when they join to return to the combination switch, you now have TWO small currents (making one bigger one) returning at the same time.

Thanks for the thoughts, and what you are saying makes complete sense, but that's not what we have here. I'm talking about a point before the two smaller currents join to make a bigger one. At the point I'm talking about, the current for each headlight is independent. The return currents have not yet been joined. The wires I'm talking about go to one and only headlight.

Here's a pic of the right side. I can guarantee that every electron coming away from the right side headlight on the thicker red/wht got to right side headlight on the thinner solid red:

The three headlight wires come out of the harness, go through the round connector and pass through the inder fender wall on thier way to the headlight bucket for the right side ONLY. (The left side has it's own three wires that come out of the harness on that side, pass through a similar connector and disappear through the fender wall on that side to feed the left side ONLY.)

After the two sides join it would make perfect sense to up the gauge, but at the point where I'm talking about every electron coming back on the thicker return wire was supplied through the thinner supply.

I'm thinking that it was a mistake in the design dept...?

[kenmataya]

i would guess its because the high beams draw more amps than the low beams. the circuitry on these cars is definitely a bit odd.

[EScanlon]

Or even simpler, the R/W wire they used is the SAME wire everywhere they used the R/W wire, and there was no need to source a smaller gauge wire for the short sections it would have been "economical" to use it for. (Which would not have been more economical overall.)

That is, it would have meant TWO different gauges with the SAME color markings, meaning that it would DOUBLE the possibilities of the wrong gauge being used in the wrong spot.

So, for simplicities sake, they used the same gauge within the same circuit everywhere. That R/W wire is ONLY used in that circuit and nowhere else in the car's circuitry.

2¢

E

Edited October 9, 2012 by EScanlon

[Captain Obvious]

Yeah, I suggested a "mistake" above, and what I actually meant was a "seemingly illogical choice to the uninformed".

I'm thinking that it was for some ease of manufacturability criteria like what you suggested... They didn't need it for the current carrying ability, but it saved them from having to stock yet another style of wire on the floor? Maybe it saved them from having to stock a different style of connector?

I've been poking around the headlight wiring lately and I saw that R/W wire. It's been bugging me since I saw it. I couldn't come up with any electrical reason for the larger gauge choice at that location, and I was wondering if I was simply missing something!

You've got an earlier year, right? Did they do the same thing on the earlier ones? Is that R/W larger than the other two?

[EScanlon]

Mine's an early 71, but it has been years since I've been into the wiring up front. When I refurbished mine, I removed all of the wiring, and cleaned and DE Grease all the connections etc. so I haven't had to get in there for a while.

I may be working on it this weekend, if the items for my Roadster don't pop up first, and if so I'll look.

E

PS, Richard, update your profile with your car's info.