Raising 79 620

[Trod8812]

Does anyone know what this wire goes to, it is coming from the brake/tail lights

Are those hooded up correctly

 

 

[distributorguy]

Sorry but this post is going to sound really harsh, but its important.  

 

Crusty old original ground strap held in place with crusty bolts to crusty metal.  Clean everything up and replace the ground cable with new.  

 

You have so many different color wires spliced in everywhere it hard to tell where the problems are coming from.  4 crimps in each alternator wire just within 2' of the engine?  Are your fingers hiding the 4th wire color?   :confused:

Start eliminating those band-aids and fix each one correctly with as few splices as possible - like zero.  One circuit at a time.  Eventually you'll eliminate all the resistance that causes heat and hopefully this will all happen before the harness starts on fire.  I've put out a few car fires in my years.  The ending is never good.  They're always caused by dodgy wiring or plugged catalytic converters which both cause excess heat.  

[banzai510(hainz)]

the photo with the swtich look like the unprotected wire is cut, You do this ?   I really don't think it will cause the fusebox getting hot

 

 

that orange wire running to the back was added for something/ Fuel pump? Light ? Stereo amp power?

 

 

the alternator T wires, if you didn't change them and they worked before then they are fine.

[Trod8812]

No I did not put that switch in there I put an actual Datsun switch in there and I just found this off of the negative cable

[banzai510(hainz)]

I see a black box for a light relay? a H4 harness then all this wire running around

[Trod8812]

The ground wire with the yellow wire nut coming from the negative of the battery

[banzai510(hainz)]

if goes to nothing take it out.

 

if near the distributor some mayb ground the distributor as some have a mate plug but if just goes to nothing pull it out

[Trod8812]

That wire went to the earth ground for the running/headlights but now the fuse is getting hotter faster

[distributorguy]

Bingo!  You found a huge ground that needs to be hooked up. Ground every circuit that's getting hot and you'll see wire temps cool down.  

 

Resistance creates heat.  Poor to no ground = high to infinite resistance = hot wires.  

[Trod8812]

Yeah but when I hooked that up it got worse

[distributorguy]

Then you didn't hook it up to the proper location, or its not giving you a good ground.  Again, old shitty grounds with poor connections don't help.  

[sebpv]

since we're on the same topic, can someone tell me what that long dark connector he was holding above the starter is? I read there is a fuse holder somewhere connecting the alt to the battery. I just want to know the what/where/how...thx

[Trod8812]

Would it make a difference if I ground somthing to the battery vs the body

[Trod8812]

When I check the fuse for continuity it has continuity until in turn on the switch or press the brake

[distributorguy]

Your fuse loses continuity when you turn that circuit on?  So does the fuse burn out as soon as you turn it on, or the voltage through the fuse causes your continuity meter to read inaccurately?  How many Amps are in that circuit?

[Trod8812]

Arround 9 amps and it's a 10 amp fuse. I thought that you were never suppose to put I higher amperage fuse in place of what itcalls for. The fuse does not blow it just gets super hot

[banzai510(hainz)]

when you mean lights on You mean the headlamps? or just the running lights On it gets HOT?

 

if headlamps then maybe somebody put H4 55/60 watt bulblamps and its still stock wire harness.

[Trod8812]

No the headlights are regular sealed beams, it's the marker light fuse that gets hot when the marker lights are on

[datzenmike]

The only resistance in a circuit should be the load... in this case the marker lights.

 

First make sure you have the correct fuse value for it. Another thing is the maximum current  should not be very close to the fuse rating... for example 14.5 amps on a 15 amp fuse. It should be lower than this, like 10 or 12 amps. See if there is some other draw on the same circuit... maybe someone added extra lamps or over wattage bulbs, driving lamps? wired in a stereo to the dash lights  

 

 

If fuse and current values are ok...

Resistance causes heat at the resistance, so if the fuse is getting hot you have some resistance between the fuse and the clips that hold it. Maybe tarnish or oxidation. Could be the heat has softened the tension in the clips and they don't grip the fuse tightly enough. The wires that connect to the fuse clips may be tarnished and causing this.

 

The alternator does not connect to the fuse box, it charges the battery. The battery is connected to the fuse box.

[FrankRizzo]

No the headlights are regular sealed beams, it's the marker light fuse that gets hot when the marker lights are on

 

Also consider disconnecting all the marker lights, turn the circuit back on and connect them back up one at a time and see which ones are causing the problems. 

 

Then you could focus on those.

 

.

[Trod8812]

 

I am not sure I understand this diagram correctly. Is a body earth ground a ground wire out of the light wiring harness to the body then to the frame?

[distributorguy]

Its a big heavy wire bolted to the chassis.  Size matters.  You can't use some little 12 gauge wire.  It may overlap the headlight wiring at the same bolt.  Both need to be attached to clean metal with a clean bolt.   Yours looks to have been cut off.  Do not be tempted to crimp an extension onto it.  Solder on additional wire if needed, or run a new one from the battery clamp bolt (preferred) minimum 10 gauge.    

[Trod8812]

So is there a difference if I come from the negative of the battery to the body to the frame or is that what you are talking about because on the wiring diagram the black wire that goes to all the grounds of the marker lights, on wire comes from the negative post into those wires then comes back out and goes the the body&earth

[Trod8812]

You know what I am thinking, there are suppost to be three black wires. One supply's power to the fuse box and the other two are grounds for the lights. I am thinking that power is going through one of the grounds or one is not hooked up

[distributorguy]

Despite what the factory did, I weld a bolt to the frame and ground the battery, engine, and body all to that one bolt, plus various other locations on the frame, since its a welded structure that carries a ground exceptionally well.  Body panels don't work near as well due to how they are connected - bolts and spot welds.  A big weld holding a bolt to the frame is indisputable.