Wireing not lookin so good

[converted_to_datsun]

I'm having Wireing issues lately. Just yesterday I looked out my window at my house and saw a little smoke comming from my truck then as I walked over a ton of smoke. When I popped the hood I found one of my horns burned up because of a short caused by a split wire rubbing on a bracket. And before that my headlights quit working and it looks like the wires have been getting a little too hot in a sketchy connector someone rigged up

 

 

 

Does it sound like something as simple as old wires or am I having a more serious problem?

[I'm BLUE]

I am not sure as I dont own a 620 but that doesn't sound right unless key was in "on" position or a bad relay? Idk

 

Replace any (+) wires/bare connections that maybe in the same predictament.

 

Make sure to execute hot solder joints and heat shrink wrap/electrical tape/liquid electrical tape

 

Quality wiring connectors will work ok if you can't/don't solder

[ggzilla]

Sounds like your 620 might be missing the Fusible Link. It is what prevents fires when a short like that happens.

[68Datsun510]

Sounds like 30 years of wiring hacks thinking they are electricians... You may need a new engine harness :/

[converted_to_datsun]

The horn gets constant power cause you can honk when the key is off and the fuse did blow after a bit but I think it was too hight amp might be why is got melted so much.

 

Might be right about the Barnes but I hope not.... I'm not an electrician so I'd rather fix what I have I guess I dunno at this point

[68Datsun510]

The horn switch gets constant power, but you shouldnt have voltage AT the horn unless your actually honking...

[converted_to_datsun]

Yea it makes no sense but the horn wasn't blowing when it shorted so I have no clue how there was power to melt it. For now it's unplugged and taped off the melted wires. I

[ggzilla]

The horn on my Datsuns has constant power through the Fusible Link, but no ground until you press the button.

[68Datsun510]

Wow, thats odd... On 510s the horns ground thru the body.

[datzenmike]

You're forgetting the horn relay. There is battery power through the horn relay coil then to the steering wheel horn button and to ground when pushed. When energized, the relay connects power to the horn which is grounded.

[68Datsun510]

I was only referring to the horn itself, after the relay.

[pharouh]

Time to do some serious wire tracing.

Do you have a factory service manual?

Could a bad ground do that? Check for bare wires,wires twisted together,and anything that doesn't look 'right'.

And see if the fuses have the right rating.

[ggzilla]

yes, like mike says, I was referring to the horn relay. It's hot all the time, and then sends 12V to the horns when the button is pressed. It's very close to the horn.

[the nice machine]

well, here is the wiring diagram for the 1979. mine is a '79 too, and i spent the first few months fighting electrical problems. it is the most complex wiring of all of the 620's. the good news is, you are about to get good at dealing with wires.

[ggzilla]

First thing check your Fusible Link. It's on the battery cable, in the wiring diagram.

[the nice machine]

oh man reading this thread is bringing back some bad memories. as far as your headlight problem goes, i don't think this could make the connector hot, BUT...

most of the electrical problems in my 620 were because of the turn signal assembly. your headlights, horn, turn signals and brake lights run through it.

the turn signal assembly on a '79 is mostly made of plastic, it is old now so it is brittle and little bits chip off. on mine the headlights only worked sometimes, turn signals only worked sometimes, etc. i rebuilt it and it worked but a month later more brittle plastic chipped off and everything stopped working again.

maybe the problem is in there somewhere.

sorry to add to the confusion, but that is my two cents.