Tail Lights

[Toyz]

I will look at my '64's today to see if there is a harness which looks like your pic. Red is normally the feed wire to the ts flasher and brake lamp.
Paul

[F164]

I spent a couple hours studying the wiring diagram this morning.

What has me baffled is that the fronts and rears are both opposite of what they should be. I would think something is connected backwards, except the connectors only plug one way.

A couple questions:

I made a set of M-M, F-F jumper wires for the tail lights. When I plug them in (rewiring the tail lights) the work as they should. The park lights are still opposite.

Does the cluster ground only with sheet metal screws to the dash? That's all I have.

I have 3 spade terminals on my cluster VR. 2-M, 1F. I of the M connectors has nothing attached to it so I have a live M spade terminal on the back of the cluster. Is that correct?

The wires coming off the bottom of my steering column have a M-F spade connector, they are long enough to connect to the VR, but Im not hooking that to power without knowing what it is for.

Since both the front and rear are opposite of what they should be, could it still be a ground problem? The truck was disassembled, painted, and reassembled, there is zero bare metal anywhere.. To get bare metal, I have to scrape/sand.

[F164]

Recap:

Wiring the rears opposite of what they were, everything in the rear works as it should. The fronts are still backwards.

Pics of the mystery column wires. Both wires have paint on them but they appear to be solid red in color.

Pic of my cluster VR.







I found a solid yellow wire coming out of the main harness behind the cluster that isn't connected to anything.

I do not have an oil pressure sending unit, or a wire that would connect to it. Instead I have a hard line and a mechanical gauge. What color wire should go to the sending unit and where does it exit the firewall?

[F7BIGJOB]

I don think the PO wired them correctly when he replaced the lights on my 64 flareside.

It looks like both filaments are on when the head lights are on. There are no brake lights when the headlights are on.

When the headlights are off, there are weak brake lights.

The rear turn signals work with the headlights off, but do not work if the headlights are on.

Do I need to cut the wires on each side of the harness and swap them?

For what it is worth when I bought my truck home for the first time, the factory lights [on brackets the chassis -were wired backwards] ie:dim brakes and bright running and it is how it came from the dealership new. Plugs were not cut, the bulbs were correct and never bothered the previos owner as it spent its entire life in a graveyard and was never on the road. I cut the wires at the lamp side of the plugs and reversed them-all ok. The original rear lamps were not the badge type they were round like the earlier [67-69] Chebys [May have come from bigger truck as alot was changed out at the dealership. When I put my new flareside bed on, I added badge style lamps and with the running light switch on and the hazards on I hooked the wires up so they worked as designed.
That switch at the bottom of your column, I really think it is a neutral safety switch and you don't want to put power to that.
Paul, you're up....

[F164]

I spent most of the day behind the dash.

The harness is in excellent condition, I had to fix a couple boo-boos related to the add on amp gauge and reroute some wires so I could get to the fuse box, but overall its pretty simple.

I found three wires not connected to anything:

A matching set of plugs like the ones hanging down from the column. Im going to plug them together and see what happens.

A brown wire not connected to anything. Its the female end of a bullet connector, it comes out of the main harness and is about 4 inches long.

A yellow wire not connected to anything. It comes out of the main harness and is about 6 inches long.

The heater blower doesn't work, I think Im missing a fuse. Its a PITA to lay on my back and look up under the dash at the box, but from what I can tell, one of the longer fuse holders is empty.

[Toyz]

Wow! Not much to add! If it worked at the back, swap the front. You might probe that brown wire to see if it is hot with parking lamps on.
I am at a loss as to where and why they might have been swapped, since the only common front/rear circuit is park lamps. An easy check for sufficient ground with the new front assemblies would be from the metal bucket to a bare metal point on the engine, using jumper cables if needed for length. Ground the test lamp, probe the metal housing; if the test lamp lights, it indicates a ground problem. I didn't make it to the shop today, but to my knowledge, the only original red wire under the dash fed the turn signal flasher and brake switch. I do remember some IP regulators having a dual male terminal adapter on the battery voltage side, but I don't recall anything matching your pic.
Neutral safety switch should have been mounted on the column under hood, and running from ignition switch "start" position to the "s" terminal on the starter relay. Your wiring diagram should indicate the color of that wire; it may well be red.
Unless you want the indicator lamps, I would not bother with them. You would need a new oil pressure switch, an adapter to retain the line and mount the switch, and probably wiring to the indicator lamp. The alt/gen lamp works as discussed earlier, if the system is original, the wires may be there with the required resistor; but may well be missing.
Paul

[F164]

Good call on the brown wire Toyz.

It is hot when the park lights or headlights are on.

Grounding the engine and front park light bucket does not produce any light on the test light.

The yellow wire is constant hot, it may be coming off the ignition switch.

[Toyz]

OK, I had forgotten that the brown park lamps feed wire is NOT common front to rear. The original setup had the front park lamps only illuminated in park position, not with headlamps on. So there IS a separation of circuits front to rear. Verify that your front park lamps do not light with the headlamps. If they do, it may explain how the circuits came to be reversed.
The brown wire may have fed a lamp for the radio, cigar lighter, etc. Try dimming your instrument lamps fully while checking that lead; if it also dims, check to see if the front parking lamps respond in the same manner. If they do, then the wires may have been incorrectly jumpered to accommodate that function, or the headlamp/ marker combination.
You have pretty well ruled out a ground issue at this point; if these tests don't show any change, the simple route forward is to reverse the fronts and see what happens.
Paul

[F164]

The brown wire does not dim. Could it be for optional cab or fender marker lights? I don't see anywhere to plug it in.

I have no idea what the constant yellow wire is for, Im going to tape it off.

At this point I have two choices. I can rewire both front and rear lights. My jumper wires indicate that everything will then work correctly.

Somewhere in the attic I have the engine harness off a 62 or 63 that I pulled out of a salvage yard. I could compare harnesses and see if the lights are wired differently or the same.

If I plug the wires coming off the steering column into the matching plug I found under the dash, those wires will exit the firewall through the big round plug located near the two firewall plugs and travel along the cowl to the right side of the engine compartment.

[Toyz]

Ok, still puzzling over this! With a voltmeter, or your test lamp, check the input side of the turn signal flasher. If it shows reduced voltage/ brightness; might try running a jumper from the fuse box to that point and see what happens. I still can't determine what would cause the reduction, but it pretty well has to be in that supply circuit to affect both stop and turn. If you have full voltage at that point, I would suggest trying a new flasher.
Paul

[F164]

After studying the wiring diagram, this is my conclusion:

As F78 stated, I think my truck came from the factory wired backwards.

The F and R marker lights are separate circuits, as are each turn signal.

There isn't a way that swapping any number of wires in the harness could result in all the lights being wired backwards unless the wires were cut and spliced.

I think my 64 flareside is somewhat of an oddity. It is a CC. I have never seen or talked to anyone who has ever seen a 64 CC flareside. My cab was missing the data plate, so Im guessing that either the cab or bed was swapped by the PO. The bed is in new condition, so its my guess that the styleside bed was damaged beyond repair and the PO purchased a repop flareside bed. The PO wasn't afraid to spend $, he also had a 65 F100 with a 428 crate engine in it that he paid over 10k for. Sadly, the PO has passed so I cant get any information from him.

Im going to change the TS flasher and all the fuses and button everything back up.

Before I cut any wires Im going to dig out the JY harness and compare it to mine. If they are the different I will swap them and see what I get. If they are the same I will rewire the rears and leave the fronts as is. On the front the only issue is that I cant see the TS when the park lights are on, I never drive with just the park lights on anyway.

Thanks for the assistance. I learned more about my wiring than I thought I would ever know. I also figured out why my heater doesn't work. I hope when I put the fuse in, it doesn't blow.

[Toyz]

Only problem I see there is if the turn signal circuit would barely illuminate the test lamp as stated; based on that, there just ain't gonna be enough power to make those lamps noticeable in daylight.
Paul