taillights and dash lights not working

[Pochie45566]

Hello! my first time searching for electrical gremlins so I have come to get some advice on the best way to start troubleshooting this issue now that I have checked off the basics. 

a while back my taillights and dash lights went out, my side markers are also not working. My headlights went out shortly after that. I checked the fuses to find that they all have continuity, and pulled off the steering column cover to find the red wire going to the headlight switch had come loose. After soldering that back on the headlights resumed working but the rest of my lights still do not work. 

I have read that the green wire on the switch is in control of these interior and tail lights, however I have already replaced the whole headlight switch and it did not change anything. 

Are there some common things I should check? Places I should measure with a voltmeter? let me know. Thanks! 

[SteveJ]

It's quite likely your headlight switch. Sometimes the connector melts down. Sometimes there is melting in the switch. Sometimes the contacts in the switch get coated with carbon.

Some of us have become skilled in tearing them down and repairing them.

[Pochie45566]

2 hours ago, SteveJ said:

It's quite likely your headlight switch. Sometimes the connector melts down. Sometimes there is melting in the switch. Sometimes the contacts in the switch get coated with carbon.

Some of us have become skilled in tearing them down and repairing them.

I replaced the headlight switch to no avail! the fuse for taillights was blown, but I have replaced it and nothing changed. 

[SteveJ]

In the BE section of the FSM, you will find a nice breakout of the "clearance" light circuit. Measure the voltage on the top right fuse with the switch off. If the voltage is good, turn the switch on, and measure the voltage. If the voltage dropped, you have a bad connection at the fuse box or probably the fusible link. 

See the discussion between myself and @Captain Obviousin this thread: 

 

[Pochie45566]

25 minutes ago, SteveJ said:

In the BE section of the FSM, you will find a nice breakout of the "clearance" light circuit. Measure the voltage on the top right fuse with the switch off. If the voltage is good, turn the switch on, and measure the voltage. If the voltage dropped, you have a bad connection at the fuse box or probably the fusible link. 

See the discussion between myself and @Captain Obviousin this thread: 

 

okay so with the light switch off I have 12.4v and with it on I have 11.8V. Is that a significant drop?

[SteveJ]

Nope, it tells me you have some current flowing somewhere. Make sure your rheostat isn't turned all of the way down, making your dash lights dim.

[Pochie45566]

13 minutes ago, SteveJ said:

Nope, it tells me you have some current flowing somewhere. Make sure your rheostat isn't turned all of the way down, making your dash lights dim.

yeah the rheostat is all the way up. The taillights and dash lights went out all at the same time so they have got to be connected in some manner. Is the troubleshooting protocol here to just trace it back to where im losing voltage or what is the process here? I have never done anything like this before so im kind of in uncharted territory. It is interesting that the fuse for the taillights was blown but when I replaced it they still didn't come back on. 

[SteveJ]

Well, the fuse is a 20A fuse. In my practice, I usually try to fuse 14AWG wire at 10A or less. If there was a dead short somewhere, most of the wire could have burned up before the fuse blew. You'll need to follow the breakouts in the BE section to see where you can still find voltage in the circuit. Start with making sure you voltage to ground at both contacts for the parking light circuit on the headlight switch. Work your way downstream toward the lights.

While you said you replaced the headlight switch, did you test it to make sure it was good before you installed it?

[Johnny280]

I had the exact same issue some weeks ago in the evening with heavy rain on the German Autobahn. Some people 'happily' flashed at me so i stopped and had a look at a gas station. Bulbs and fuses were ok and since i had no tools with me and had to drive another 100 miles I called the guys from ADAC (german car club - i guess equivalent to AAA) The guy did some measurements and said that most probably the switch had a problem. So we pulled off the steering column cover and had a look. It turned out to be an issue with the big plastic connector (switch was fine). We disconnected it several times and suddenly it started working again. There was definetly some discoloration to the connector and it was filled with (di-electric?!) grease. So maybe someone already tempted with it in the past or Nissan send them out this way? 

I plan to clean it up in the future. But right now it is working. 

Maybe you have the same problem.

 

btw. Car is `78 280Z

Edited September 6, 2020 by Johnny280
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