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Usain_Boat

78 280z turns off with turn signal/reverse lights

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23 minutes ago, Usain_Boat said:

Well I've already traced power for those circuits. I lose power at the fuel pump relay output (the relay clicks off) and I also know I lose power on the wire that provides power to the solenoids in the fuel pump control relay and fuel pump relay.

Do you lose power to the ignition system also?  The coil.  You're focused on the tail of the problem instead of the head.  Go all the way back to the battery.  You might even have a bad battery connection.  You haven't really said that everything else maintains power, only that certain relays lose power.  

And don't assume that voltage equals current.  Seeing voltage on a circuit just means that it has the potential to do something.  Without a ground nothing will happen.

Be the electrons...

 

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Tested with it dead, the coil has 12.8 volts as to be expected with the engine not running. Testing from anywhere on the circuit that provides power to the flasher fuse, even at the fusible link that protects the fuel pump power as well as to the ignition relay to be switched into the White/black wire gives a reading of mV to ground and the battery. With it dead unplugging the reverse lights and plugging them back in turns the car back on and while doing this I noticed the right hand reverse light is much more dim than the left hand light.

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4 minutes ago, Usain_Boat said:

With it dead unplugging the reverse lights and plugging them back in turns the car back on and while doing this I noticed the right hand reverse light is much more dim than the left hand light.

Are you unplugging each light individually, at the socket, or unplugging the reverse switch on the transmission?  You said "them" which implies both, but you have to unplug each individually if you're actually unplugging the lights at the socket.

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1 minute ago, Zed Head said:

Are you unplugging each light individually, at the socket, or unplugging the reverse switch on the transmission?  You said "them" which implies both, but you have to unplug each individually if you're actually unplugging the lights at the socket.

Yes, sorry for not clarifying. Switching the trans out of reverse or unplugging each bulb individually will return power to the wire.

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So you can unplug a single bulb, either side, and power comes back?

I don't have a solution in mind but do see that the ground wire for the bulbs is back at the ignition relay.  Same for the signal bulbs.  You might find that ground wire and either replace it with a better ground wire or clean up the connection.

My latest guess is that the ground circuit is opening due to heat from the extra current.  Similar to how the bad battery connection open up.  Find that ground wire and make sure it's right.  It could be the connection at the relay mount or the connector shown in the diagrams.

image.png

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How many ohms?  What does "good" mean?  What does "ground" mean?  "That ground looks clean".

I can only offer clues.  You decide how to run with them.  Think in terms of circuits.  Current flow.  You're losing current flow somewhere.

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Around .5 Ohms to ground where my leads have a resistance of .2-.3 Ohms. I understand that I'm losing current just baffled as to where. It stops dying in reverse with the flasher fuse pulled or the reverse switch pulled, yet I have physically traced the reverse circuit and nothing is grounded out. Also even with the reverse circuit disconnected the left tun signal still kills the car.

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I haven't exactly found the problem but narrowed it way down. I jumped the supply side of the fusible link for the trouble circuits to the + on the battery and it has stopped dying. My next step is to unwrap that section of wiring harness and look for the issue.

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Found the problem! When I cut back the tape the crimp for the white wires for the problem circuit fell apart. What is the best way to repair and recrimp this area? Also notice how much corrosion there is.IMG_20190807_121219.jpg

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Where exactly is this in the wiring harness? I can't make it out with the close-in shot.

By the way, great job on the perseverance. You're representing your generation well.

Edit: Wait, I'm taking that it's at the fusible link. So that branch wasn't getting full current due to the corrosion. When it got the extra load, the voltage would drop.

Edited by SteveJ
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1 hour ago, SteveJ said:

Edit: Wait, I'm taking that it's at the fusible link. So that branch wasn't getting full current due to the corrosion. When it got the extra load, the voltage would drop.

Exactly my thought too. The reason it was so intermittent was probably caused  by the car jiggling on the road and the resistance on that section causing it to heat up and expand just enough to mask the problem.

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1. Clean with vinegar and tooth brush until copper on both wires is bright.

2. Pull back enough insulation on the exposed end so that its copper can be fully wrapped around the exposed copper in the harness wire.

3. Solder the two together.

4. Insulate with electrical tape.

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Between 2 & 3 - Coat the area to be soldered with a good flux. That will help the solder adhere to the wire.

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5 hours ago, Usain_Boat said:

Found the problem! When I cut back the tape the crimp for the white wires for the problem circuit fell apart. What is the best way to repair and recrimp this area? Also notice how much corrosion there is.IMG_20190807_121219.jpg

Been there, done that. And now, confirmation that I was not the only owner with THAT problem. (Sorry about that0

for some pics of the issue I fought with.

Looks better than what I started with. Let me know if you need some additional white / red stripe wire. Got lots from the old harness I pulled out. Mine was green instead of rusty.

NOTE: See the electrical tape covering the two wires in the picture? If you have THIS condition here, you may the same condition THERE.  Not as bad as the "While I'm there disease" but more of the "Let's prevent another disaster"

Edited by wal280z
edit in bold
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1 hour ago, wal280z said:

NOTE: See the electrical tape covering the two wires in the picture? If you have THIS condition here, you may the same condition THERE.  Not as bad as the "While I'm there disease" but more of the "Let's prevent another disaster"

My plan was to look after I fixed this splice. Currently trying to solder the connection but I can't get enough heat into it to flow the solder. All I had was a 15W Radioshack iron so I bought a 100W harbor freight gun (I know not great quality) but I still can't get the whole joint to heat up and flow. I'm using quite a bit of flux too.

Edited by Usain_Boat
Flux

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What you may find, is upwards to an inch or more from the bare wire connection, there is additional corrosion that won't help your situation down the road.

Although I can't find it now, there are (were) some crimp-able  type connectors available. That is what the factory used - in some instances, a 4 into 1 using 12-14 AWG.

Although bulky, you could use some terminal blocks (2 terminal type) to connect the wires together. Then wrap the crap out of it. Bulky, yes. Serviceable, yes. OEM, no. <<this would be considered a 'BUSH FIX' (sometimes bush fixes become permanent, thanks @Captain Obvious)

@SteveJ and others will be able to add better ideas on how to CORRECTLY splice and connect.

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Do it in two steps:

 

1. Melt some solder on the tip of the iron then place the tip under the wire in the harness. Let the wire heat up then feed solder into it. Keep the heat on it.  Congrats you tinned a wire.

2. Wrap the other wire around the tinned section and do the same: Melt solder on the tip then heat the two wires while feeding solder... don't be shy on the heat time. It can take a while. Just keep the iron on the wire.

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@Usain_Boat

Would you do me a favor and note quote in reverse background if possible. It's really hard for me to read it.

You might be able to get a pencil torch if you can't get enough heat too it. When you hold an iron to it, hold it underneath. Remember heat rises and the wires will heat better on top of the iron

Edited by Patcon

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Well it's definitely not the prettiest soldering job I've done but it's done and the car runs correctly! I also checked the other splices around it and they were solid but a little corroded so I just put some dialectric grease on them and taped it all back up.

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