Don’t have any dash, dome or tail lights when headlights are on?

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LovetheA's

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So I just went through a bit of drama pulling the front of my engine apart to reseal my timing cover to my oil pan. Now that is all fixed I don’t have any dash lights, dome light, or rear tail lights when my headlights are on. I know I had a dome light before the reassembly of the engine. I did have a spark possibly short occur when I was tightening down the rear connection on the alternator. I didn’t pull the + terminal before attempting to tighten it down and hard some sparks shot off my 1/2” wrench. Won’t do that again. It looks like the lead that branches off and connects to the back of my alternator leads to the firewall harness. It doesn’t appear as if anything was melted or burned. Should I check the fuses in my fuse box first then after that I don’t know where to go?
Carl
 
Get an electrical diagram and trace it out.

My bet is fuse
 
Always check fuses 1st. Thats what they are designed to do...
SHouldnt have had sparks if the battery was disconnected.
Checking fuses is easier than starting this thread.
 
LovetheA's said:
I did have a spark possibly short occur when I was tightening down the rear connection on the alternator. I didn’t pull the + terminal before attempting to tighten it down and hard some sparks shot off my 1/2” wrench. Won’t do that again. It looks like the lead that branches off and connects to the back of my alternator leads to the firewall harness.
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You may be lucky with the spark show and not melted the link or other wires.
Next time, disconnect the battery's negative cable.
Yes negative. Think about it.
If the wrench accidently hits ground when removing the negative, there no sparks.

As far as the issue you asked about, it may be just the fuse. 67s use the same fuse for those three items.
Also check the firewall to engine ground cable.

upload_2020-6-18_8-52-1.png
 
Fuses can be very tricky. I ALMOST ALWAYS try and TEST FOR VOLTAGE UNDER A LOAD on circuits

"Let's take that fuse."

Let's say the fuse is internally flakey, and I've seen them. OR let's say the fuse clips are rusty/ oxidized/ corroded.

You get under there you hit the fuse clips with your light/ meter and it lights and you say "OK"

BUT IT IS?

TURN ON the parking lights (By the way in 67 parking lights were NOT energized with headlights)

Now locate the proper fuse, take your light or meter and probe BOTH clips. You should have good solid battery voltage on each clip. "Wiggle test" it a little

Also, "bad" fuse clips can BLOW FUSES and sometimes will heat them up and blow them INSIDE THE END CAPS where you cannot see them. This turns into an intermittent that can be a bit hard to find.

This is because the clips with a poor connection BUILD HEAT in the fuse end caps
 
67Dart273 said:
Fuses can be very tricky. I ALMOST ALWAYS try and TEST FOR VOLTAGE UNDER A LOAD on circuits

"Let's take that fuse."

Let's say the fuse is internally flakey, and I've seen them. OR let's say the fuse clips are rusty/ oxidized/ corroded.

You get under there you hit the fuse clips with your light/ meter and it lights and you say "OK"

BUT IT IS?

TURN ON the parking lights (By the way in 67 parking lights were NOT energized with headlights)

Now locate the proper fuse, take your light or meter and probe BOTH clips. You should have good solid battery voltage on each clip. "Wiggle test" it a little

Also, "bad" fuse clips can BLOW FUSES and sometimes will heat them up and blow them INSIDE THE END CAPS where you cannot see them. This turns into an intermittent that can be a bit hard to find.

This is because the clips with a poor connection BUILD HEAT in the fuse end caps
Click to expand...
Yep, thats why I touch both sides of the Fuse barrel itself with a grounded test light, with the circuit on. Just a little pressure to stab each side.
Cannot be sure by looking and sometimes you blow them by removing and re installing them.
 
First off everyone I’m still in the very rudimentary learning phase when it comes to electrical in the car. I have a lot to learn so if it’s not explained in steps and clearly I get lost. Sorry about that but I’m just being honest and really trying to learn. I also know that fooling with electrical without disconnecting the power isn’t smart. I was foolish when first tightening down the hot wire connection to the back of the alternator and that is why there was a spark off the wrench. It wasn’t a big spark and very quickly I pulled away. I don’t see any damage to any wires or leads. First step I will definitely check the fuses first. I also have read that the one post off the back of the OEM style alternator is for the positive(hot) connection and for the ground connection. I’ve read that the ground connection to the alternator has to be from the alternator to the engine block? Also the ground has to be contacting through bare metal and unpainted surfaces? I think that maybe the ground isn’t secure properly and maybe not heavy enough guage wire. My alternator has been rebuilt and puts out about 60 amps. I have a probe testing light and volt meter. Thanks again gang for all the help with everything.
Carl
 
First. Accidents happen and we learn from them, so don't agonize over it.
LovetheA's said:
I also have read that the one post off the back of the OEM style alternator is for the positive(hot) connection and for the ground connection.
Click to expand...
That will be an easy way for you to discriminate good info from bad. Anyone who is saying the output stud or the wires attached to it are ground should be ignored. They are clueless.
As you can see in the schematic, the black wire is alternator output and joins with battery output at splice.

LovetheA's said:
I’ve read that the ground connection to the alternator has to be from the alternator to the engine block? Also the ground has to be contacting through bare metal and unpainted surfaces? I think that maybe the ground isn’t secure properly and maybe not heavy enough guage wire.
Click to expand...
Correct. The output circuit of the alternator uses the housing as ground. The housing is bolted to the brackets and the engine. That part of the connection is going to be pretty good.

There is a ground connection from battery to the engine block. Then, on your car, there should be ground wire from the back of the block or rear of the right cylinder head, to the firewall. That's the body ground.
 
When the wrench touched ground while on the nut, it briefly completed a circuit.
Current flowed from the battery positive to the battery ground terminal.
upload_2020-6-18_15-15-3.png

If you had held it firmly against the ground it would have been a good connection and as many electrons as possible would have moved through until...
that fuseble link melted.
That's what its for. To prevent a major melting of other wires if the battery is accidently grounded.
 
LovetheA's said:
I’ve read that the ground connection to the alternator has to be from the alternator to the engine block? Also the ground has to be contacting through bare metal and unpainted surfaces? I think that maybe the ground isn’t secure properly and maybe not heavy enough guage wire. My alternator has been rebuilt and puts out about 60 amps. I have a probe testing light and volt meter. Thanks again gang for all the help with everything.
Carl
Click to expand...

The alternator ground on traditional US cars is almost never a problem. They are firmly bolted to the engine with the mounting bracket and belt tensioner, so ground is pretty much "there." And yes, the big black wire is DIRECT to the battery through the ammeter circuit. IT IS NOT fused, except for the not-very-reliably-effective fuse link. So be careful of that one
 
So the first thing I’ll do is check each fuse in the fuse panel under the dash. I’ll put a test light in each connection to make sure it lights up. I know that may not guarantee that the fuse box isn’t shorting or corroded but it’s a start. Then I took pics of all the grounds on my car. Fire wall to engine block, steering column support bracket to dash frame. Also the thick hot lead to the back of my alternator. In the pic you will also see a green wire that runs of the main lead from the firewall junction. That plugs into a male tab in the back of the alternator. The problem is that I don’t know where to find the ground for the alternator to check it it’s up to snuff? Is that green wire lead the ground?

587AACCE-AE27-4C1A-83E7-C9F790343AA9.jpeg


999A12FD-8CD7-41E4-9ED2-EB630D7285E6.jpeg


0B49F616-41F6-4686-ADFF-29A016FF6DC9.jpeg
 
Theres no wire grounding your alternator. That green wire is the Field. To keep it simple...Another way to check to see if your Alternator is grounded, (with battery connected) You can clamp your 12 volt test light to the POSITIVE side of the battery and (carefully) just touch the light to the alternator body it should light up if its grounded properly. The Alternator grounds through the several mounting bolts to the engine and shouldnt be an issue, as long as the engine is grounded, through the chassis.
You can also touch any metal component thats bolted to metal to check for ground like the Voltage Regulator on the firewall.
It s just to check that the components are completing the path to ground.
DO Not touch any hot leads while hooked up to the Positive.
 
LovetheA's said:
Also the thick hot lead to the back of my alternator.
Click to expand...
That is the alternator output wire. Think of it as going to the main splice.
When the alternator is producing power, electricity is flowing from the alternator to the main splice.

LovetheA's said:
The problem is that I don’t know where to find the ground for the alternator to check it it’s up to snuff? Is that green wire lead the ground?
Click to expand...
Ok Maybe I wasn't clear.
Mattax said:
Anyone who is saying the output stud or the wires attached to it are ground should be ignored. They are clueless.
Click to expand...
and maybe this wasn't clear either.
67Dart273 said:
The alternator ground on traditional US cars is almost never a problem. They are firmly bolted to the engine with the mounting bracket and belt tensioner, so ground is pretty much "there."
Click to expand...
What we are saying is what Joey just said: there is no ground wire to these alternators. The alternator grounds both circuits through the brackets and engine.
One circuit powers the spinning electromagnetic. The green wire is the one that supplies power supply for that.
The other is the output circuit consisting of the non-moving windings and rectifiers to convert the induced A/C into DC power.


This can work, but its not factory. I would take the twist out but Del knows more about whether it matters.
999a12fd-8cd7-41e4-9ed2-eb630d7285e6-jpeg.jpg


FWIW Factory location was here. Mine is covered in insulation due to the headers but its the easiest photo for me to find.
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To trace why there are no Dome, Tail, or Dash lights.
1. As Del mentioned, front parking lights normally are only on when the headlight switch is pulled out to the first click. Tail lights should of course be on as well.
2. Since the Brake lights, Tail and Dome light share a fuse, see if the brake lights work.
3. If the brake lights are also out, then check for power at the fuse.

I just happen to have the fuse box from my 67 barracuda on the bench.
Looking up at the fuses, second one in from the driver's door should have power.
upload_2020-6-19_17-22-33.png

The contacts the arrows are pointing to are connected to the battery.
In other words they are always HOT unless the battery is disconnected.
upload_2020-6-19_17-40-15.png


If the tail, stop, dome, fuse is blown or not getting power, then the instruments lights can't get power either.
So solve this part first.
 
Everyone thank you so much for all the help in explaining the situation to someone who isn’t as well versed in the electrical aspect of things. Explaining it in greater detail and simpler has been a tremendous help. In fact the problem was at the fuse box. One of the fuses shown in the previous photo was blown. I replaced it and also lightly sanded all the metal hold down clips in the fuse panel and coated with dielectric grease. Everything is functioning great.
 
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