Short or something electrical

T

tyler

Senior Member
Been working on my A to get it ready for the summer. Was running fine and everything was working until I fixed a few things, now it wants to spark when I go to hook up the ground cable, didn't do that before.

I put in a repro switch to replace the repro switch that didn't fit behind my instrument panel, came with it's own cable. Replaced my ammeter because I saw sparks from behind it once last fall and don't trust it. Also just rebuilt the steering sector and just re-installed it.

I've unhooked the ing. switch then touched the cable to the battery and still get sparks, same with the ammeter and the light switch at the bottom of the steering colunm. I'm electriclly challenged and will probably need to get help tracing this down but any suggestions welcome. Oh, re-wired the car last summer, new harness from Sac. Vintage Ford, no problems at all before this.
Tyler
 
is this a 6 v postive ground? if so the + goes to the frame.
are you running a stock system with generator or alternator
 
Hi Tyler,

Assuming one has a (+) ground battery, very simple analysis mentioned over & over among electricians & auto repairmen:

1. Get a multi-meter & learn how to turn the dial to read DC-volts & Ohms.

2. Ohms test: (a) Set multi-meter dial to ohms, touch red test wire to black test wire & one should see an ohms reading. (b) Get a 12" long auto electrical wire & strip 1/2" or so of insulation off of both ends & touch one end with red, other with black test wire -- one should see same ohms reading indicating "continuity". (c) Cut same wire in half, test both ends, one should see "no" continuity -- that simple. (d) End of ohms test to insure electrical wire has continuity & wire is not damaged or broken inside the insulation.

3. Volt test: (a) Set multi-meter to DC volts reading. (b) Touch positive (+) battery post with red test wire & touch negative (-) battery post with black test wire & read volts. (b) Touch negative (-) battery post with black wire & touch a "grounded" steel part of the car, & one should read about the same volts because the same negative current is flowing to the positive steel all the way back to the grounded battery. (c) Electrical current flows in insulated wires like water flows through water pipes -- if the wire insulation is broken, it leaks electricity like a leaking water pipe leaks water, hence with wires one sees dry sparks in lieu of wet water.

4. Electrical test: (a) If one has proper ohms after testing continuity in all wires & also continuity through all electrical connections, (junction box, coil connections, switch connections, etc.,) electricity will flow uninterrupted like water in a pipe all the way to the end of the line. (b) If there is a break in the wire insulation, or a break in any insulated item, one sees sparks because the wire is leaking electricity traveling from negative to a positive grounded item just like one sees a leak in a water pipe. (c) Start all testing from the original source, (the battery), & follow each & every wire, (just like water pipes), & each & every connection, (just like pipe joints), all the way to the end of each electrically powered item -- it is that simple.

5. Problems: Some people have snake problems, some spider problems, some math problems, some frog & lizard problems -- you electrical problems should be over after following the water pipes.

Hope this helps.
 
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Tyler,
If you are learning, and even if you are an expert, sometimes it is better to "fix" one thing at a time and test the car as you go. That way , if something goes wrong, you can go back to the last thing you did and undo it. When you make multiple changes at one time, it can be more difficult to trace a problem.
Mike
 
Hi Guys

Stock system, pos. ground, generator. Sorry I didn't say that at the start.

Mr. Colvin, thanks for taking the time to explain all that. Even I get it now, will purchase a multi-meter tomorrow and see how it goes. Was I correct in trying to find the problem by un-hooking things one at a time and then connecting the battery to see if it still sparked?

Donvito, yes, that's what I should have done and will certainly do from now on.

Thanks for the help everyone, I'll report back when I find the problem.

Tyler
 
Update:

Checked for continuity and had juice going everywhere it should but I also get a reading when I test from the starter cable post to the steering colunm. That ain't right, is it? What would cause that. Also, headlights don't work since I "fixed" things, where they did before.

Tyler
 
How big was the spark? Did it indicate the brake light was stuck on (little spark), or did it indicate a dead short (big sparks)?

I'd start by unhooking the horn/lights wire at the cutout output terminal. That will cut the horn and lights out of the circuit, which cuts the possibilities in half. If it still sparks, then also unhook the generator wire at the same cutout terminal. That will eliminate the cutout and generator. Now you are down to the coil, switch, and ammeter, unless it's something in the starter switch.
 
Hi Tyler,

Am I misunderstanding your question in reply #6 as to ain't right or is it?

1. The starter cable post is directly connected to the battery negative(-) post through the negative (-) battery cable; hence the starter cable post is negative(-) or as some call it, "Hot".

2. The steering column is bolted to the chassis frame & should be grounded (+) because the battery positive (+) post is connected to the same grounded (+) frame.

3. If one checks multi-meter DC voltage from the (-) starter cable post to the (+) steering column, (& if one has both (-) continuity to the battery & (+) continuity to the battery between these (2) verification points), one should get a DC voltage reading between the (-) starter post to the (+) steering column which is similar to that when testing the (-) battery post with the (+) battery post.

4. In other words, a DC voltage reading between the (-) starter post & the (+) steering column should be normal.
 
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On your post #6, headlights don't work........
Start there.
One of the "bullets" may have separated giving you a short. As Tom says "cripple' the headlights and horn circuits, then ck to see if you're still sparking.
Paul in CT
 
Thanks guys. Hopefully I can get a chance to work on it again later tomorrow and will let you know what I find.

Tyler
 
Update;

Thought I'd take a look this a.m. when I had a few moments to spare, figured I'd take Tom's advice and unhook the wires on the generator one at a time and see what that did. Looked at the car and then remembered Tom also mentioned the starter switch so I looked closely and saw that the battery cable seemed to be touching the switch so I bent it up so there was no longer any contact and voila!, no more sparks and the headlights now work.
Mr. Chauvin, I'm going to take your advice and get a multi-meter and learn how to use it. Also, from now on I'm only going to fix one thing at a time and then test.

One more question; one of my headlights has always been noticably dimmer than the other one and I understand that it's probably not grounded well. What would be the best way to improve the ground?

I can't thank you all enough for the help you've given me.

Tyler
 
Hi Tyler,

Humble Opinion:

Both Model A headlight & tail light problems are usually traced to about a 98% probability of poor grounding.

I just "grounded" (2) "new" headlight sockets with (2) new ground wires connected to the chassis on the other end of the wires as follows:

1. Install the headlight reflector on the socket.
2. On the socket, (with a fine felt tip marker), mark how deep the reflector fits on the socket. (From this mark, to the rear of the socket, is where a ground wire can be attached so as not to interfere with the reflector fitting over the headlight socket).
3. Get an automotive wire type male spade wire connector, remove the plastic insulation, neatly bend the spade in a concave manner to fit prependicular to the round socket, & afterwards, neatly solder a #12 wire to the wire end of the male spade connector.
4. On the socket, behind the felt tip mark, place a small amout of solder.
5. On the in-side of the concave part of the male spade, place a small amount of solder.
6. Place the concave male spade on the socket, (perpendicular to the socket), & heat same until the two neatly join & add a bit of solder on the top of the spade connector. (In the gunsmith world, this joinery is called "tinning").
7. Run the ground wire through the headlight conduit to a ground in the engine compartment.

This should allow your headlights to be grounded for at least until you wear out (10) mufflers on your Model A.

No doubt many different ways to accomplish this but because of lack of leisure time while working, I always attempt to do repairs & modification work once -- hope this helps.
 
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