Mystery wire on early Z

[ramjet]

This is my first post, so don't be too tough on me. Early '70 Z Serial 01769, original owner, stock, except Petronix points replacement module. Even have the original AM radio. Here's what I've got:

Where: Among the wiring bundle located under the dash, passenger side, wrapped in the snap-on vinyl cover.

What: A WHITE/black wire connected at one end to a three-terminal white plastic connector shared with a GREEN/yellow and a YELLOW/green wire. This male connector is inserted into a female that has a WHITE, a WHITE/black and a blue wire.

Problem: One end of the first-mentioned WHITE/black wire is adrift, hanging. The only thing that has stopped working is the radio, but the electrical diagram in the shop manual doesn't indicate any WHITE/black wire related to the radio.

What I've checked so far:

1.The condition of all fuses. OK

2. Front and back of the fuse box. It's pristine.

3. Charging system. OK

4. All instruments including clock. OK

5. Hazard flasher. OK (This IS connected to a W/b wire, but apparently a different one).

6. All lights, signals, dome light, glove box light. OK.

7. I'll check instrument lights when it gets dark, but I think they're OK.

Question:

What the blue blazes is the function of the loose wire?

Thanks for your patience with a blundering amateur.

[Zs-ondabrain]

The only other Black/white wires I can find on my diagram is from the ignition and one that goes from the Voltage regulator and taps into the Kick-down switch for an automatic transmission.

Is the wire "Cut" or does it have a connector on it??

If it ain't broke, don't try and fix it,

Dave.

[EScanlon]

Take a look at the following diagram. It shows the colors for many of the multiple connectors in the passenger cabin.

If you look just behind the Shifter (disregard that this is for an automatic) you'll see a 3 wire connector, the one with all three connections "stacked" one above the other. It's color legend is WB, W, L; or White/Black, White and bLue. That's the connector for your radio. Re-insert that WB wire back into the connector and your radio should function again.

This isn't shown in the Wiring Schematic. The WB and W are for the speaker, the Blue is for power, and should have a separate in-line fuse. Some cars instead of a WB wire had a WL (White/Blue).

HTH

E

[ramjet]

Right on the money! That was it. Radio's banging out the oldies on AM like it was 1970. The thumbnail's a keeper. My original has a similar schematic, but yours seems a bit more detailed. What manual is it from?

Now about these dim instrument lights...I've cleaned the little green lenses, replaced the bulbs & replaced the rheostat. Poor ground?

[m4xwellmurd3r]

I think dim instrument lights is just a Z thing. A lot of people hate that so they get LED's and wire them up with a small resistor to drop the voltages to the proper levels. the difference between stock and LED is like night and day

[EScanlon]

Roger:

While lots of guys have made some attempts at using LED's and trying to get the angle just right; removing the green lenses, and even trying light up instrument faceplates, I think my solution is the easiest and biggest bang for the buck. No offense meant to the other guys, but if you're not looking to change the color, add special effects, or wanting to be blinded by your dash, then try my method.

I simply painted the inside surface of the instrument cans with the brightest gloss white paint I could find. I used a paint called Polar White that commonly gets used on the underside of R/C Car's Lexan Body shells.

Since it's white and glossy, it reflects every bit of light that shines through the green globes inside the instrument cases. I even use my rheostat to turn DOWN the brightness.

There's a couple of points to bring up:

Silver paint has been touted, however, in the color wheel scheme of things Silver is Gray. Additionally, most brush on silver paints that I've seen aren't very reflective. Spray can paint can be, but now you have to remove EVERYTHING including the green globes AND still mask in order to use it. However, most silver paints still don't reflect light as intensely as bright white does. Add to it that the green globes are actually filtering the light so that it is tinted green and you've reduced the actual light being reflected ... off a grey surface.

LED's are bright, but they are also very directional. The end result can be bright areas on parts of the edges, but they don't "fill" the edge as well as the bulbs did. I'm sure someone has done a few tests, but even after the savings of never having to change those bulbs again, the initial expense is such that I'll stick to the OEM style bulbs. I bet the LED's would also benefit from painting the inside of the cases.

Speaking of the OEM style bulbs, forget the 3 watt bulbs, get the 3.5 or 4 watt replacement. I recently used Sylvania 53BP, although I recall 67's also being good. I'll have to double check. I think you need about a dozen total (2 each Tach and Speedo, one each "eyebrow" instruments, 2 turn signals, one high beam and one brake). I swapped bulbs simply because many had already burned out, and I decided to start with a fully new set. I think another 30 years will be fine for my investment in bulbs.

But that's the simple fix I have.

HTH

E

P.S. The diagram came from a Clymer's manual, but IIRC I also saw it in one of the FSM's out there. There are a couple more diagrams showing all the connectors in the Engine and Rear of the car as well as the Single Wire connection Diagram. I've uploaded them here before. Do a search on posts with me as the author.

[ktm]

Escanlon, I agree 100% with your recommendation about painting the housings. I converted all my dash lights to LEDs (not like Dave's, I used individual LEDs spaced around the gauge face) and I still painted the gauge housings. The gauge faces are lit by indirect lighting. Anything you can do to increase the albedo of the gauge housing the better.

You mentioned silver paint and I agree that silver is similar to gray. However, there is Chrome paint that works very well. I used the Chrome paint to paint the inside of my front turn signals.

[Zs-ondabrain]

Right on the money! That was it. Radio's banging out the oldies on AM like it was 1970. The thumbnail's a keeper. My original has a similar schematic, but yours seems a bit more detailed. What manual is it from?

Now about these dim instrument lights...I've cleaned the little green lenses, replaced the bulbs & replaced the rheostat. Poor ground?

The dash lights are typically dim due to old bulbs, bad grounds, and lack of sufficiant power to the lighting circuits of the 240z's. That's was the 2nd reasoning for the PLH or Parking Light Upgrade Harness that I make. It's major function is to relieve the amperage that flows thru the fusebox and the combo switch. The resistance in the parking light circuit is the best explanation for your dim dash lights, as they are on the parking light circuit. After installing the PLH, the dash lights, as well as the side markers, front markers and rear taillights were brighter.

I personally removed the inner, green plastic domes, especially after finding that the factory painted half of each green dome white. Just removing those improved the lighting. Then I went to www.superbriteleds.com and ordered 11 BA9 wide angle, white LED bulbs. Then I painted the lip of the front gauge plate, silver. (not the can or housing but the black front peice, so the light would reflect off of that and onto the face of the gauge.

The result was an ever so slightly blue in the white light. It's much cleaner, brighter and I can tell you how fast I'm going at night now.

Sorry the pics are so big, I was in a hurry.....

[EScanlon]

Bo;

No doubt you used the Spray on Chrome Paint (Krylon IIRC). Pretty nice stuff, I've used it myself on another project and have even applied Candy over it and it looks quite nice.

I can see the Chrome Spray's benefit on the Front Turn Signal backs as there are times when the reflector (if it is still there) is either rusted, de-laminated (chrome layer gone) or simply missing.

On mine, I was lucky in that I only had a small area or two that had delaminated and they took well to metal polish, as such all I had to do was apply some metal protectant (not polish). I did, however, paint the flat surfaces of the backing with the Polar White paint. Same with the tail-lights. I've had people think that my lights are on ... during the day.

The key with the Chrome spray paint is that it allows the aluminum particles to align well and essentially "skin" together forming a mostly continuous surface. That is probably the key requirement for good reflectivity, and the reason we polish metal, glass and even painted surfaces.

Silver paints alone don't do that, and trying to sand them smooth generally does not generate that evenness. In fact, sanding silver is a general PITA as it can quickly show "layers".

But to highlight my point on Silver being "Grey", spray a scrap piece of metal, wait till the silver dries and you get a nice glossy and shiny finish. Then spray it with Clear. The end result is ... Grey.

FWIW

E