LED external lights and associated electrical issues (1977 280Z)

[seattlejester]

^ I agree, both are useful. Get the proper LED flashers and enjoy both benefits. I guess I was thinking more from a modernish car perspective.

[Alan birk]

A sad number of LEDs are junk. Make sure you get a reputable brand! 

[bawfuls]

On 5/21/2018 at 9:59 PM, 1970 240z said:

Hope this helps.

 

Using a Test light or Multi-meter:

Check for power at the fuse block(see diagram of fuse block), both ends of the fuse should have power. Power on one side and not the other means bad fuse or fuse connection.

 

Check to see if you have power (from the fuse box) on #2 in diagram (Grn/Blk) wire at the connector on the column that leads to your Combo Switch. If so, Jumper #2 to #1 (Grn/Wht) which leads to the marker lights and your markers should light up.

 

If lights work with jumper but not when plugged back into switch and in on position then switch is the issue.

(1977 280z Wiring)

 

bumping this thread with mo' problems

 

In trying to repair my switch, I eventually broke it, so I bit the bullet and ordered a refurb off ebay. In the meantime, I'm trying to test new lights by just jumping the connections in place of the switch.

 

With the ignition at Acc and nothing jumped, I am getting power at the fuse box at the "Power to Combo Switch for Park" point in the image above. If I jump #1 and #2 in the combo switch image, the side marker lights come on, along with turn signals (not flashing obvi) and the tail lights. But no headlights (this is with original headlights installed). I also see no power at the headlight connections in the fuse box (on either side of the fuses) in this condition (the orange and orange/white leads on the top left in that image).

 

tl;dr: when using a jumper to bypass the combo switch, marker lights come on but no headlights and no power at the headlight fuses

 

Any ideas?

[jhm]

Your headlights and running lights should power on irrespective of the ignition switch position (I.e. they should power on even with the ignition completely off).

 

It sounds like you believe your combo switch is working properly; and if that's the case, have you tested the circuitry to ensure you have 12V going into the combo switch on the headlight circuit?

[bawfuls]

I'm not using the switch because mine is broken and the new one hasn't arrived yet. I'm jumping the pins at the connector where the switch plugs in. I have power at the fuse lead that feeds the combo switch connector, but I did not check for power at the connector itself, which seems like an obvious oversight now. Will have to check tomorrow.

[1970 240z]

Hope this helps (1977 280z):
Here I've added the headlight circuit From the Fusible link into the Combo switch wire (Wht/Red) , then From the combo switch to the Fuse box (Red), then From the fuse box to the headlights.
Common issue is bad/dirty connections at the Fusible links if your not getting power on the White/Red wire at the combo switch plug. As said earlier, the Key switch is not required to be on for power to be at the headlight circuit.

 

 

Edited September 20, 2018 by 1970 240z
Removed duplicate image

[bawfuls]

Alright so the new combo switch is here which should make testing easier.

 

I checked without the switch connected and I've got 12V at #2 and #4 (at the steering column).

 

I am also seeing the tail lights come on when the battery is connected but the combo switch is in the OFF position (wtf?). This is the case even with the combo switch completely disconnected.

 

With the new switch connected and turned on, the marker lights come on but the headlights do not, same as before.

Edited September 20, 2018 by bawfuls

[1970 240z]

#4 should  be getting it's power from #4b,  which in turn gets power from #3 by going through the switch. If your getting power at #4 when it's disconnected from #4b, then pull you headlight fuses, you may be getting a back feed of power through the fuses.

 

also, Check the round connectors where the main harness connects to each headlight harness. Pull apart the connector, clean and test for power. These connectors can get dirty.

[bawfuls]

Resurrecting this thread as I've come back to the issue again after 6 weeks of other things. So I have verified power at fusible links, fuse box, 4B, etc.

 

I checked power at the headlight connectors themselves, and found something weird: with the light switch on, all 3 contacts at the lights read 12V, even the one that should be ground. Tracing things back on the wiring diagram, I found 12V at the Earth connection on the combo switch. That's E on the combo switch table in the above images. When the switch is in the OFF position, this connection reads no voltage, but when on the second (high beams) position it reads the same 12V as 4B. It still reads no voltage when in the first on (low beams) position, BUT in this position the ground connector at the headlight reads 12V

 

This.... means my combo switch is wired incorrectly or shorting something? I can't find any difference in the ground connections between my refurbished and my old combo switches. (The old one did work intermittently ~7 months ago).

 

What other sources could be causing this ground to see 12V when the light switch is on?

 

I am extremely confused now.

Edited November 4, 2018 by bawfuls

[1970 240z]

Bawsfuls, sorry for the slow response, i just saw that you had some more questions. Did you get this resolved already?

[bawfuls]

Nope! Been keeping busy with other things, but it’s time to come back to this now. I was considering replacing the wiring along with the turn signals/flashers/relays if I can’t figure this out. I have not yet researched how to do that though.

[1970 240z]

I recently was working on a 77 280z turn signal switch. As a by product I developed a headlight issues that sounds much like what your experiencing. I found that if the black ground wire running between (connecting) the turn signal switch and the headlight switch was not connected then the headlights would not come on. Driving/marker lights all worked but no headlights. Once reconnected all worked. Check that this wire is connected on your setup. It's the unmarked wire on the far right in the headlight combo switch diagram above.i

I believe this wire completes the circuit to run the headlights through the high/low beam switch.

 

As for power in your ground wire, that make sense as power ultimately starts at the + battery and needs to return to the - battery, effectively a circle. So as the power runs it's route it will show power along the way unless the circuit is broken/open (such as a switch).

Edited December 13, 2018 by 1970 240z

[bawfuls]

I just double checked, and that unmarked black/ground between the headlight and turn signal switches is connected.

 

My turn signals don't work currently either, though the hazards do flash them properly (even with LEDs swapped out up front).

 

New flasher units are cheap, should I start there? Is there a reliable aftermarket flasher unit that will play nice with LED bulbs without the need for load resistors?

 

I also realize now that I should have disassembled and cleaned the hazard switch while the console was out of the car, is that worth doing now? I've read it can interfere with the turn signals if it's worn, even while the hazard function still works.

[1970 240z]

This is the flasher I'm using with my LED turn signals. I've used this on 2 cars (my 77, and a friend's 75) with no issues.

 

https://www.rockauto.com/en/parts/tridon/novita,EL12,flasher,1013

[1970 240z]

There is a way to by pass the Hazard switch with 1 jumper wire. I'll post how to do this once I review which 2 wires are involved. I've done this a couple of times when trouble shooting the Hazard switch.

 

Also, (I'm sure you've done this) flick your headlights high to low and back afew times. I've seen where these old switches can get stuck in between modes and no headlights light.

Edited December 13, 2018 by 1970 240z
fixed some typos

[bawfuls]

Thanks, saw those flashers on Rock Auto but O'Reilly also claims to stock several that are compatible so I'll stop by there today and pick a couple up. They're so cheap that even if they don't work it's nbd.

 

edit: replaced both stock flashers with this one from O-Reilly, no change in behavior. Hazards still work, turn signals (and headlights) still don't.

Edited December 13, 2018 by bawfuls

[1970 240z]

For a 1977 280z:
To bypass the Hazard switch to allow you turn signals to work, Jumper (on the harness side) the Green wire to the Green/yellow wire. If your turn signals work after applying the jumper then you know the Hazard Switch is an issue and not working, it likely will need to be rebuilt or replaced. Usually the contacts inside the switch are dirty and need to be cleaned.

 

Edited December 20, 2018 by 1970 240z
corrected spelling errors

[bawfuls]

Thanks for that diagram, worked like a charm! Both turn signals worked just fine with that jumper (even blinked at an appropriate speed with LEDs up front, thanks to the new flasher).

 

Now I will look for hazard switch rebuilding guides/replacements. edit: opened up the switch, cleaned the contacts off, put it back together, and signals now work even with the hazard switch installed.

 

Just need to get to the bottom of the headlight issue now...

Edited December 15, 2018 by bawfuls

[1970 240z]

Excellent on getting the turn signals working!
Now on to your headlights. Here is a basic troubleshoots guide I put together for someone else, I believe you have done much of this but take a moment to review it to see if anything in it helps.

Here’s a sorta step by step process for checking.

1) Start by checking the Engine bay main fusible links connections. The one closest to the fender (outer) and the front (away from the firewall) is the one that provides power to the headlight switch. These often get tarnished or corroded at the Blade connectors. Once these are cleaned and you’ve verified power on each side of the connection then move to the column.

2) Check the large White/red wire at the column; this is power from the main fusible links. This is where power enters your switch. When the switch is turned on, power exits the switch to the fuse box by way of the large Red wire with the bullet connection. At the fuse box the power is split into 2 circuits, one for each headlight.

3) Check for power at the two headlight fuses and ensure the fuses to the fuse-box connections are clean and good.

4) Since both headlights are affected, it’s not likely that these two separate power-circuits to the headlight bulbs are the issue.

5) The headlights share two common ground circuits, one for Low beam & one for High beam. Since both high & low beams are affected it is not likely these individual ground circuits from headlights back to the Turn Signal switch (High/Low selector).

6) There is a wire at the column that connects the Turn signal switch (High/Low selector) to the Headlight combo switch. Check that connection; this is where the ground circuit routes to the Head Light switch, which then continues out the large Black wire with the Blade connector to ground.

There is no factory relay in the headlight circuit. There are aftermarket kits or people modify to add a relay. If yours has this mod. then the wiring and relay for this could be a suspect as well.

Edited December 17, 2018 by 1970 240z
Corrected text shown in red-previously stated closest to firewall

[1970 240z]

You can bypass the High/Low switch to confirm the headlight circuit is working properly.

 

Edited December 17, 2018 by 1970 240z
corrected minor typo