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bawfuls

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

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Posted (edited)

Working on my '77 280Z, and had planned to replace all the old bulbs with LEDs from superbrightleds.com. Last week I replaced the brake lights, reverse lights, and front side indicators (whatever those ones on the side are called) with LEDs and everything worked great, new ones were clearly brighter, etc. Although right around that time the headlights stopped coming on, which I didn't pay attention to at the time (but in hindsight this should have been a warning maybe?)

 

Today I went to start on the turn signals. I replaced the front driver side bulb with an LED and it came on just fine, again noticeably brighter than the old one on the other side, great! (The dash is out of the car right now so I can't test turn signal flashing yet, I have the load resistors but haven't spliced them in yet). Then I replaced the passenger side one, and no lights would turn on. So I put the original incandescent bulb back in the passenger side, still no lights come on. Then I put all the original incandescent bulbs back in, removing all LEDs from the car. Still no lights come on. I did nothing else on the car between the install of the first and second front signal LEDs, it was maybe 10 minutes.

 

Multimeter still gives 12.28 volts across the battery, and the head unit/speakers work so it's not a complete electrical failure but something to do with the lights. I checked ground connections (in particular the two at the front of the car right next to the horns, which I tried wiring directly to the battery negative via some alligator clips) but they are all fine as far as I can tell.

 

I don't know what steps to take next. I have the full wiring diagram for the vehicle (http://www.atlanticz.ca/zclub/techtips/wiringdiagrams/F77ZCAR-WIRING1.pdf) but I don't know where to go now, any ideas?

Edited by bawfuls

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Definitely check the 4 big fusible links by the battery. One of those feeds the lighting for the car and those have messed me up so many times. They often have a loose connection at the blade terminal or the wire snaps off.

 

Also make sure you didn't remove your center console for whatever reason. I chased having no turn signals all day once to figure out it was because the hazard switch in the console wasn't connected.

 

Is your multi-function switch working for any other functions (wipers?) maybe it got disturbed when replacing the blinker relay. 

 

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The center console has been out for several weeks. I know the turn signals won't flash with it and the dash out, but the front ones at least came on in running light mode before, and the brake lights and side lights and headlights all came on fine with the console and dash removed just a few weeks ago. The fusible links looked alright last I checked, but I can clean off the contacts just to be sure. The multi-function switch does work for the wipers currently.

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I would for sure grab the hazard switch from the console and plug it back in the car. All the lights usually work in my 280 but the second I removed the console and that switch all kinds of weird stuff happened. Turn signals in many vehicles will partially ground through the running lights and cause weird things to happen when they loose part of the circuit. Not saying its your problem but it only takes a second and won't cost you anything. Just trying to help. 

 

 

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Posted (edited)

I will try it with the hazard switch, but to be clear the lights all worked for a couple weeks without the console or dash in the car so there is likely another issue at work too.

Edited by bawfuls

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Uh really sounds like a fuse blew to me.  Check your fusebox.  then check the fusible links.  You can pull the hazard from the console and test with it. though I have found cold solder joints on the Hazard switch a couple different times.  That makes for some fun troubleshooting. 

 

Phar

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That's a good point. I just checked with an LCR meter and these two fuses I pulled both measure 0.1-0.2 Ohms, which ought to mean they are fine. I checked all the rest of the fuses in that box on the passenger kick panel and they all measured less than 0.2 Ohms, except the one labeled "Floor Temp Lamp" which looks busted anyway. It's only a 1 amp fuse, surely it can't be the culprit for the lights issue?

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Hmm the bending in the fuse means it was using quite a few amps of the rating. Question is was it going to blow and something else went first. Continuity setting is your friend in tracing wires.

 

If I knew more about the 280z wiring harness I would offer advice. On a friend's honda, he installed an LED backwards for one of the interior lights and shorted his entire interior light circuit. We replaced the fuse and it blew again. Found the bulb, flipped it and it stopped blowing. 

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Posted (edited)

As a side note, I replaced my turn signals with LEDs as well on my 77 280z. I didn't use any load resistors. I simply replaced my flashers with electronic ones from Rockauto, Oreilly's has them too. They've been working great for a couple years now.

Edited by 1970 240z

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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)

1941043226_77-Markerlights.JPG.780d4c7e4649a7bb0b029fcc0e5af94f.JPG

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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)

1941043226_77-Markerlights.JPG.780d4c7e4649a7bb0b029fcc0e5af94f.JPG

 

Thank you for this, things worked exactly as you anticipated here. Power at #2, jumping 2-1 brought lights on but they don't come on when plugged in and with switch on. Time to search for combo switch repairs I suppose. 

 

Since this was working before I put in LEDs and then broke once I did, that makes me suspicious that a repaired switch will again fail with LEDs. From what I can tell via searches here and elsewhere, this isn't a typical issue though? The load resistor issue should matter for the flashers but I'm not even at that point yet.

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Yeah you're probably right on that. I think the lights worked only some of the time before, I really didn't test them a lot until now. Obvious answer is to just rebuild the combo switch as many have done in the past.

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17 hours ago, bawfuls said:

 

Thank you for this, things worked exactly as you anticipated here. Power at #2, jumping 2-1 brought lights on but they don't come on when plugged in and with switch on. Time to search for combo switch repairs I suppose. 

 

Since this was working before I put in LEDs and then broke once I did, that makes me suspicious that a repaired switch will again fail with LEDs. From what I can tell via searches here and elsewhere, this isn't a typical issue though? The load resistor issue should matter for the flashers but I'm not even at that point yet.

Glad the diagram helped.

I agree with seattlejester as the LED's are easier on switch not harder. I've run mine for 3 or 4 years with zero issues.  As you've likely already found, there are write-ups describing rebuilding the switch.

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