1973 Thing Reverse lights - reverse switch wiring

[keith808]

Okay I am resurrecting an old post for some clarity.

1. reverse lights are attached to switch at the nose cone.
2. two wires go up and come through the firewall.
3. The short female wire from tranny attaches to the short black male adapter coming out of the main harness. This little balck wire is just on the inside of the engine compartment.
4. Longer wire with the bakelight attaches to the positive side of the coil.
5. 8 amp fuse goes in bakelight.

Do I have this right?

[Semper_Dad]

Sort of.

12VDC power for the reverse lights come from the 15 (hot) pin of the coil (Black wire).

It then goes through the Bakelite fuse holder in the engine compartment (Black Wire)

Then it goes to the switch on the transmission (Still Black wire)

From the switch on the transmission (Black wire) it goes to one of the taillight's reverse lights (blue wires)

Taillights are already grounded.

Take a look at the wiring flow chart located in the technical section. Pretty easy circuit to chase out.
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[keith808]

[Semper_Dad]

There's a connector in the engine compartment (T1c) then it splits out to the T4 connectors under each taillight

I'll have to check tomorrow but I believe the entire reverse light wiring is NOT a part of the main wiring harness. It was kind of an add on.
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[keith808]

Semper- Thanks Let me know what you see.

[Semper_Dad]

I took a look at my engine compartment and I followed the power wire from the 15 post on the coil to the Bakelite fuse holder. My fuse-holder pretty much sits on top of the carburetor. The wire then continues inside a small protective sheathing over to the right side (passenger side) of the engine compartment and down toward the engine seal. I assume it goes on to the transmission switch. Too cold outside to drag myself under the car to look what happens after the switch. I did find each of the T4 connectors inside the engine compartment under each tail-light.

The harness containing 3 wires indicated by A are
1) 12VDC coming from fuse panel-connects to 15 on coil (Black wire)
2) Red/Green wire from oil pressure switch
3) Grey/Green wire that goes to the defunct Diagnostic plug

You can see another black wire indicated by B going up and over the carburetor. In fact you may even be able to see part of the fuse-holder. That wire continues to the right side of the engine compartment and down to the engine seal.
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[keith808]

thanks semper

I know it leaves the tranaxle nose cone area and ends up back in the enginge compart just the fire wall. It is only a few inchs though and I was curious how the power then gets to the 4ways. Does it clip to that other short wire.

I bought a napa version bakelight, until I can get an OG one, to test it out tomorrow I will let you know if I get the buggers to turn on.

[Semper_Dad]

[keith808]

4way sorry I meant the T4 connector wrong terminology.

[doublecanister]

Hey Keith808,
Fyi all,

do yourself a favor, if your "reverse lite fuse cigar block thingy"
isnt mounted in a holder (my holder is missing)
make SURE the wires that connect to the spade connecters on either side of that device dont protrude out, if they do it can cause an electrical connection which will short out if it touches ground.

Mine did this on the coil side of the fuse block, the "+" input's spade connector "tail end" stuck out about 1/16th of an inch, just enough to happen to move and ground out to the fan shroud.
It hit (one of the bendable square tits that weave the wire harness).
Again, it grounded between the coil and the "coil side" of the fuse block thingy.
needless to say, it fried about 8inches of wire, NEVER blew the fuse
it was shorted before the fuse, and it did shutdown the engine.

Twas a simple fix, but is scared the hell outta me, all I could smell was rotten plastic smoke, I thought I was having an engine fire.
And MAN did it smoke!!
GOOD RULE to move them fuel filters outta that area!!
I've since made sure the spade connetor 'backends' are covered.
and my fuel filter is out of the way.
I put as much of it as I could in some of that coiled wire loom.

Freak event but could have been trouble had I been somewhere I couldnt have pulled over out of the way.

Just so you all are aware, this could have been BAD.

T.

See in the Photo, this Blue part protruding is what I'm trying to explain, cept on mine (both sides were the metal tail part of the spade connector)

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2020 - Mustang Eco Boost [High Performance]
1973 - Thing
1966 - Mustang GT- Fastback
1951 - Ford F1 pickup Flathead V8

[keith808]

[Semper_Dad]

Glad you resolved the problem.
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[chrisRphoto]

Hi all,

I have a 1997 Mexican beetle. the reverse lights don't work. This version has electronic ignition so..no coil as such. The wiring is different. The "funny" thing is...according to the owner's manual...fuse #12 handles the reverse lights, the dash light, the fuel gauge and hazard lights. That fuse blows as soon as I turn the ignition on but everything still works except the reverse lights. I don't have that fuse behind the fan shroud. The wires are all in a neat wiring harness that splits in two at the firewall. One goes to the left back light and the other to the right. All integrated reverse light, regular light, stop light and indicators. How do I figure this out? (bulbs are fine)
Chris.

[Semper_Dad]

Without a wiring diagram it's going to be pretty hard figure out.

Power from the ignition coil was just a convienent way for VW to add the reverse light circuit to the car. That kept them from having to add it to the wiring harness loom.
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[chrisRphoto]

Thx Semper,
Yeah, I know....to be honest, even with wiring diagram I don't have the first clue.
From the fuse block under the dash, all the wires go into the taped and covered harness.
I have one "melted" black wire with white stripe coming from fuse #12 and going into the harness. Where it comes out through the firewall..I don't see the wire. I disconnected it from the fuse block and turned the ignition...fuse doesn't blow any more....so that was the culprit. But...what does that wire go to?? I have to put the car through a safety inspection..but have no back-up lights. I'm stumped!!

[chrisRphoto]

Here's an idea...tell me if I'm out of my mind.
What if I cut a hole right above the reverse-light switch on the transm.(so I can get at it) run a wire with a fuse from the battery to the switch and another from the switch to the back-up lights. Disconnect the original wire to the reverse light bulb and attach the new one.

[citroen]

that will work all you need to make them work is a hot on one terminal and a wire on the other side to a bulb all the switch does is to make current go to the lights when you close the circuit or push the switch in which is what happens when you put it in reverse dont forget the fuze and maybe a rubber grommet where you cut the hole for the wire so the wire does not rub the insulation of on the frame

[chrisRphoto]

Exactly Citroën.
Was planning some major insulation around the area where the wire goes through the hole.
Fun project for a Sunday.
Now just hope that the switch is in fact, working!!
If only I knew which of the two wires at the switch are faulty....from the fuse block to the switch or from the switch to the light....would eliminate one wire and make life easier.

[chrisRphoto]

Boy..am I p..... off!!
Did a nice neat job of soldering a fuse in place, extending wires with connectors at the ends, shrink tubing averywhere...jacked-up the car and started connecting the two wires to the back-up light switch....first one on....then the second lip just broke off of the switch!!!!! AAArrrgggg!!!
Now I need to order a switch. Did I mention I live in the caribbean and no parts available down here?
The safety inspection is going to have to wait another 2 weeks or so.
Makes you want to break something!!

[locky]

I have been following all of this and I don't have said "bakelite" but I do have this.

I think I have all of the other wiring dialed in, and this is the only connection that is available for my Reverse that I can see. Anyone else have this one. It has a vw stamp on it.