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

[bawfuls]

-verified power at fusible links

-large white/redstripe wire at the column that goes into the combination switch does NOT have power, but when I plug it in anyway, I get 10V at each of the headlight fuses if the combo switch is in the high beam setting. No power at the headlight fuses when combo switch is off or set to low beams. This... shouldn't be possible without power at the white/red, no?

[1970 240z]

The fuse box "headlight" circuit (see diagram earlier in posts) has a White/black wire feeding to it from the Ignition relay & Fuel Injection so power could be coming from this circuit and back feeding back up to your switch if your key is "On". The High Beam position is likely providing a grounding route, the Low Beam position may have tarnished contacts and may not be completing the ground. I think we should focus on getting power to your large White/red stripe wire at the column. There is a 6 wire connector at the passenger foot area against the firewall. It is likely behind the plastic mount for the Dash harness connections, its possible this connection is dirty.

Edited December 17, 2018 by 1970 240z

[1970 240z]

Also, I corrected my basic troubleshooting, the fuseable link servicing the headlight switch is the outer/front fuseable link.

[1970 240z]

Any progress?

[bawfuls]

I got sick right before the holiday and then the usual obligations took my time, so I'm just getting back to this today.

 

Unfortunately some complications from my EV conversion have now impacted the headlight issue. Long story short, I left the 12V battery connected over the long break and it drained (because I did not have the DC-DC converter powered on to keep the 12V battery topped up from the high voltage system while I was away). The 12V battery now reads ~350 mV directly across it's terminals. It seems to me that it should not be able to discharge that deeply, but I presume it is now dead and will need to be replaced. 

 

The fact that it drained so completely while I was gone also indicates that there is some kind of leak path in the 12V system which I'll need to track down once I've got a fresh battery installed. Maybe this is also the cause of the headlight issue?

 

Not sure that I've articulated it in this thread, but I am converting this Z to fully electric drive, so I have removed extensive systems from the car. In addition to all the obvious (engine, fuel lines, fuel tank, radiator, alternator, etc) I also cut out all the EFI wiring and the ECU. I was careful to make sure that the wiring I removed was only the EFI and ECU system based on the car's wiring diagram, but still that could have introduced complications to the 12V wiring system.

Edited December 28, 2018 by bawfuls

[bawfuls]

Finally back in the shop with some time to look at this issue again, and it feels like I'm going in circles. I replaced the 12V battery with a fresh one and started the process again.

 

-I've got power at the white/red stripe going into the combo switch on the column now (I checked the connection behind that white plastic harness in the passenger foot-well area as well, it didn't work at first but did after cleaning the contacts a bit)

-I've got 12V at each of the two headlight fuses on the fuse box, but ONLY when combo switch is on high beams, not when it's off or set to low beams

-ground connection between combo and turn signal switches is intact and reads within 1mV of chassis ground

-no power at any of the 3 headlight contacts, unless the switch is on high beams, in which case i get 12V at all three

[1970 240z]

On 12/16/2018 at 1:17 PM, 1970 240z said:

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

 

Lets try removing the Turn Switch out of the equation;

1) unplug the 6-wire connector from the switch but leave the Black Ground wire running between the two in tack.

Did this remove the "extra" power from the Headlight plug?

2) With the Headlights off ground the Red/black wire on the harness side (see diagram above for location).

3) Turn the Headlight Switch to the "on" position, do you have Low Beam lights?

4) If so, then the Turn Signal switch is suspect and likely needs to be opened up and have the contacts cleaned.

 

Edited January 21, 2019 by 1970 240z

[bawfuls]

-unplugging the 6-wire connector for the turn signal switch did not remove the "extra" power from the headlight plug

-grounding the red/black wire on the harness side did not enable low beams in the "on" position

-grounding the red/white wire on the harness side DID enable lights in the "high beam" position, but when I unplugged a headlight to check the voltage, it's only getting 10V on the high connection. My stock lights come on with this (not super bright), but the new LED lights don't of course because they need 12V

 

As best I can tell, this is how the lights behaved when I first got the car and had it running (limping) on the stock engine. Headlights did not come on in the low beam position, came on but weren't very bright in the high beam position. That makes me feel a little better about having not fucked things up more when I ripped the engine out.

 

So this means... there's some issue with the ground loop connections? Not sure how to diagnose further.

 

Edited January 21, 2019 by bawfuls

[1970 240z]

I suggest putting your stock headlight bulbs in until we can get both hight & low beams working correctly. That would remove the led variable from the equation.

 

Did you check voltage at the headlight bulb connector or at the headlight sub-harness connection (round connector) at the inner fenders? There are two Sub-harnesses, one for each headlight just on the inside of the fenders near the radiator bulk head. That round connector at the sub-harness can get tarnished and need cleaning, resulting in too much resistance.

 

Power runs from the fuses (one for each headlight) through the C-4 (White) connector located in the passenger foot well (see pic), through the engine bay harness, then through the headlight sub-harnesses, to the headlight bulbs.

1) Clean the Fuse connections well. What is the voltage at the fuses?

2) Clean the C-4 (White) connector located behind the white mount up in the passenger foot well, check voltage here. (Red/yellow=Lft headlight & Red=Rt headlight). With this connector disconnected you should have no power to the headlight bulbs.

3) Clean the Sub-harness connections as well and check voltage. Are you getting only one 12v power source at each of the Sub-harness connectors? Each of the connectors contains two grounds (high & low beams) and one 12v (pwr from the fuse box; Red/yellow=Lft headlight & Red=Rt headlight).

4) What is voltage at each of the headlight bulb connectors after cleaning & testing through steps 1-3? Do you have multiple 12v power sources here but not at step 2?

 

It's normal to have a little voltage drop as we go along the harness, but it shouldn't be excessive.

Refer to the previous diagrams for wire colors as needed.

 

 

Edited January 22, 2019 by 1970 240z
Added additional info using numbering

[bawfuls]

I just checked voltage again at both the round connector sub-harness and at the headlight bulb connector, and they were the same (this is with the high beams pin on the 6-pin connector at the turn signal grounded directly to chassis). voltages on these three pins: 11.4V, 0.8V, 10.9V. That's the middle pin, the fatter one, that reads low while the other two read high, all of these are measured against chassis ground.

 

Voltage at the two headlight fuses are both 11.0 currently. I just checked the battery directly and it's reading 11.88V right now (lower than the ~12.4 I was seeing on Monday, I have the car "on" right now so the DC-DC converter should be recharging the 12V battery from the high voltage pack).

 

Voltage at the C-4 connector is 11.98V for both headlights. This is a bit funny because when I checked the voltage directly on the battery terminals immediately after this, it read 11.88V.

 

Verified no power at any of the sub-harness connectors for either side while the C-4 connection is open.

 

Still feels like a grounding issue because I only get power when I directly ground the high-beam pin at the turn signal harness as you instructed in your previous post, and I get no power at the headlights when I ground the low beam pin and put the switch to low beams.

[bawfuls]

There is definitely something draining my 12V battery faster than expected when the car is off. I typically disconnect the negative terminal when I stop working on the headlight issue and leave for the day, but I left it connected Monday night I think and as noted the battery was down today to ~11.9 from the 12.4 or so it was at on Monday. It has been recharging for the last 15 minutes or so and is up to 12.15, so my recharge circuit is working as intended at least.

 

I've no idea if this drain is related to the headlight issue or not. But I also have no idea how I'm going to chase down the leak. I guess I need one of those multimeters that has the clamps so you can check current through wires, then just start from the battery and eliminate branches one by one?

[1970 240z]

4 hours ago, bawfuls said:

I just checked voltage again at both the round connector sub-harness and at the headlight bulb connector, and they were the same (this is with the high beams pin on the 6-pin connector at the turn signal grounded directly to chassis). voltages on these three pins: 11.4V, 0.8V, 10.9V. That's the middle pin, the fatter one, that reads low while the other two read high, all of these are measured against chassis ground.

 

Voltage at the two headlight fuses are both 11.0 currently. I just checked the battery directly and it's reading 11.88V right now (lower than the ~12.4 I was seeing on Monday, I have the car "on" right now so the DC-DC converter should be recharging the 12V battery from the high voltage pack).

 

Voltage at the C-4 connector is 11.98V for both headlights. This is a bit funny because when I checked the voltage directly on the battery terminals immediately after this, it read 11.88V.

 

Verified no power at any of the sub-harness connectors for either side while the C-4 connection is open.

 

Still feels like a grounding issue because I only get power when I directly ground the high-beam pin at the turn signal harness as you instructed in your previous post, and I get no power at the headlights when I ground the low beam pin and put the switch to low beams.

 

 

Looking again at the schematics, there is a wire branching off of the right headlight wire after leaving the fuse to feed the High Beam Indicator bulb located in the speedometer. The ground side of the High Beam Indicator connects to the High Beam ground wire circuit (Red/white wire)  "the fatter one, that reads low" so it will always have some small amount of voltage due the small amount of power passing through the bulb, so I would say your 0.8v would be expected there.

 

For the right head light, the Red wire should be the only wire with near full battery voltage,

For the left head light, the Red/yellow wire should be the only wire with near full battery voltage.

 

Interesting data collected from my 1977 with all switches connected.

Battery Voltage = 11.94v (engine & Key off).

Ltf Headlight Sub-harness connector:                                                                          Rt Headlight Sub-harness connector:

High Beam: R/y=11.88v                                                                                                   High Beam: R=11.87v

                      R/w=.12v  (won't light a Test Light)                                                                               R/w=.14v (won't light a Test Light)

                      R/b=.00v                                                                                                                             R/b=.00v

 

Low Beam:  R/y=11.92v                                                                                                     Low Beam: R=11.92v

                      R/w=11.92v  (lights Test Light but is less bright than R/y) (likely less amps)         R/w=11.92v (lights Test Light but is less bright than R) (likely less amps)  

                      R/b=.00                                                                                                                                R/b=.00v

 

I don't have a reason yet for the higher volts but lower amp 11.92v R/w on Low Beams vs .12v on High Beams, other than I'm sure it's feed back from a circuit in the switches.

I thought I would share this to see how it corresponds to your results. I am running the stock headlights though all my other lights are LED.

 

Edited January 24, 2019 by 1970 240z

[1970 240z]

On 12/16/2018 at 1:17 PM, 1970 240z said:

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

 

 

I just pulled the dash on my 77 project and thought I'd do some headlight circuit testing. This car has the OEM style headlight bulbs. With the Key Off, Turn sign switch and headlight switch fully removed,  I get no power to the fuse box as expected. I connected only the Red wire and the White/red wire to the Headlight switch. With the Headlight switch off there is no power to the fuses as expected. Turning the Headlight switch fully  on and there is power to the fuses as expected. Checking the power at the round Sub-harness connector of one headlight (in this case the left side) I had power at each of the 3  wires, not expected. I realized the power is routing through the right-side bulb which is still connected. To verify I disconnected the Right-side Sub-harness, this removed power from both the Low & High Beam wires at the sub-harness connectors. I still had 1 wire with power (Red on the right & Red/yellow on the left) in each Sub-harness connector as expected as these wires are coming from each of the two fuses. At this point I reconnected both Sub-harnesses. At the column, in the 6-pin connector, I temporarily grounded the Red/black which activated the Low Beams, I moved over and then grounded the Red/white which activated the High Beams as expected. Keep in mind that I still ONLY had the Red wire and the White/red wire connected to the Headlight switch, no other wires and key was off.

 

See if you get the same results.

On a side note, I actually had an experience where BOTH headlights were burned out, likely from a voltage regulator issue causing over voltage. Look closely at your bulbs to ensure that you aren't having a similar issue with the High Beam circuit.

 

Edited January 29, 2019 by 1970 240z

[1970 240z]

Did you find the issue?

 

[bawfuls]

I did not yet, unfortunately. I've been prioritizing other things on the car since the headlights reliably work (with the old bulbs) in the high beam position, though they aren't high beam bright. I finally got the car running this past weekend and there's a lot of other bits I'm focused on at the moment. Your help has been invaluable though and I will revisit this thread once I've got other things dialed in (suspension, flywheel re-balance, etc).

[bawfuls]

Spent a couple hours on this again today for the first time in awhile, because this week the headlights stopped working all together, even on the high setting. I verified continuity on the ground side of things (headlight sub-harness to the white C-9 six-pin connector, from there to the combo switch, etc).

 

Now I'm getting a symptom I saw previously (I think, maybe 8 months ago, hard to remember), which is full battery voltage (13.6V with the car on) at the middle (fatter) connection on the headlight sub-harness when the headlight switch is on the HIGH position (no voltage when off or LOW). From my reading of the wiring diagram, this pin should be the GROUND for the high beam position. This is very confusing! This pin is wired directly to the white C-9 six-pin connector on the passenger floor area, and I've verified ground continuity at that point.

 

 

Edited May 1, 2019 by bawfuls