Hot tip from a cool guy.

[Old Henry]

For diagnosing loss of current in electrical circuit.

Many months ago I was struggling with cranking speed when trying to start the engine. It would crank very slowly and often slow down to a dead stop. I thought it was a bad battery that I hadn't had for long so traded it in on a new one. No better. I think I may even have dismantled the starter to find a problem but that wasn't it. So, I PM'd my "go to guy" for all things electrical, Kevin Koates, way down under in Auzziland, to get his ideas. He simply said, "Feel all along the circuit for anything hot. There will be your problem." Surely it couldn't be that simple, could it?

So, next time I had the cranking problem I opened the hood and started with the battery cable from the battery to the starter solenoid, cool as a cucumber. Then my hand hit the starter solenoid. It was not only very hot but had melted the plastic insulators around the posts. Replaced it and all was well.

Then, two days ago, I decided to replace one of my headlamps that had been dim on high beam for a long time thinking it was because of age. The new bulb was just as dim. I then remembered Koates' suggestion so started feeling along the wiring to that bulb. When I hit the butt connector connecting the vehicle wiring to the bulb wiring it was warm. I cut it out, stripped the wire ends, twisted them together, and secured with a wire nut. Solved the problem. The bulb was bright again.

Then, today, after fighting this problem with my high and low beam circuits shorting together when wet, I did the same thing. I started to feel along the circuit from in front of the radiator back into the engine compartment. When I got to where the light wiring connected to the vehicle wiring with old butt connectors, they were warm. I unwrapped all of them and the wires and found lots of bad insulation and connectors that were my problem and hopefully fixed it.

So, for any electrical problem, start with feeling along the circuit (after it's been powered on for a while, of course) as Koates suggested. It's worked for me three times out of three so far.

Thanks, Kevin

[trainguy]

A perfect example of KISS

[V8COOPMAN]

Amazing, especially after the dozens of stupid suggestions from the peanut gallery to REPLACE that rotten wiring.........BEFORE that thing burns-down. DD

[41panelmark]

Thanks for the info.

[Old Henry]

Originally Posted by trainguy

A perfect example of KISS

One of my favorite mottos.

[Terry,OH]

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Don't use wire nuts on your car electrical wiring. They will come loose! They are made for use in stationary areas with a quiet environment. Soldered or PROPERLY crimped using the PROPER connectors and terminations are more like what you need. They will keep you driving without problems. I agree with v8coopman it seems to be time to replace.

[tubman]

I had a similar problem in an O/T vehicle. I have one of those cheap hand-held infrared thermometers that I used to track down the problem. It can detect differences much more sensitively than your fingers ever can, and it can work from a distance away, so you don't have to contort your body to get your hand in out of the way places. (Important when you get to my age.)

Repair or replace is a judgement call.

[corvette8n]

These connectors have sealant in them, I consider this a better temporary fix.

https://www.superbrightleds.com/more...85bxoCo6fw_wcB

[RB]

Also it might be noted that shrink tubing with sealant is also available at most hardware & home centers, works well in all areas, particularly those prone to moisture such as hitches etc.

[tubman]

Speaking of heat shrink tubing, I find I use it a lot. (One of those things that may effect a "repair vs. replace" decision.) The problem with it is that it can be tough to get installed. A friend of mine in the electronics business put me onto some specialized heat shrink tube that shrinks at a 3 to 1 ration, which is significantly more than the stuff you can get from the hardware store. (It's helped out a lot in some situations, but it is kinda expensive.) Also when working with heat shrink, it's best to have a heat gun; I've seen it done with a Bic lighter, but I never have any luck with stuff like that.

[Tinker]

So there is no circuit breaker or fuse under the dash for a 1947 ford? I never owned one, but if I can remember right the 42' sedan I had, had a fuse.

To me a new Sacramento ford wire harness looks more original then shrinkwrap, tape, and wire nuts. We run new tires don't we?

To each their own.

[JSeery]

A 47 would have a dual circuit breaker setup on the lighting, but it does have only one fuse on the clock.

[Old Henry]

Originally Posted by Terry,OH

Don't use wire nuts on your car electrical wiring. They will come loose! They are made for use in stationary areas with a quiet environment. Soldered or PROPERLY crimped using the PROPER connectors and terminations are more like what you need. They will keep you driving without problems. I agree with v8coopman it seems to be time to replace.

I wrap them with friction tape and they're fine.

[V8COOPMAN]

Originally Posted by Old Henry

One of the nice things about a 6 volt system without any fuses is that a short will heat up so you can find it without actually burning anything. I've had a lot of experience with that in this 69 year old car (which I've had for 57 years) that is still as original (including all wiring) as I've been able to keep it. I would be very surprised if anyone running an original stock 6 volt system could actually have any kind of fire caused by faulty wiring. Maybe that's why Ford didn't put any fuses at all in the car (except the clock???). Even the only circuit breakers, for the headlights, never kicked off when both filaments were energized by my short.

Craig.......After a long career dealing mostly with the power distribution and UPS systems powering a huge air traffic control facility, I thought I understood a little bit about electricity, along with some reasonably-effective troubleshooting techniques to use when problems arose. I'll be darned, but your single paragraph above makes me realize just how dumb I must be with electrical stuff. I honestly never knew that 6v stuff only heats-up enough to make it easy to find the warm spots during a short.

One little tip here for ya none-the-less......there are SHORTS, and then there are the type of SHORTS that you haven't experienced....yet! Your little short between conductors (luckily) that you experienced powering both filaments only amounted to a temporary parallel circuit coming from a "like power". It's going to be an entirely different set of circumstances when that rotten cloth insulation allows a bare wire to touch any part of that grounded body. During a "dead short" situation like that, the conductor (wire) flows uncontrolled current from the battery to ground.........not unlike holding a wrench across both battery terminals. That relatively small wire will almost instantly glow red (more than WARM), at least all the way back to the high/low beam switch. That's why it's able to set that old dry cloth wiring (as well as any others in the harness) ablaze, releasing ugly amounts of black smoke. Of course, leaky fuel and grease can make it even more interesting. It happens so fast that you won't have a chance to get your door open to start looking for a wrench to undo the battery cable.

I'd really hate to see you lose your car based on your clear mis-conception of "6v auto electrics 101". A short to GROUND can really screw-up a guy's day. And when was the last time you tested those 69-year old circuit breakers? DD

[Barry-ct]

With all the driving you do with the car, it's time to get a new harness, so you can enjoy you trips. I'd hate to not see your travel journals and pics of that part of the country because your car burnt up on you, And I know you'd be very unhappy! That harness is on borrowed time.....

[Old Henry]

I deleted my post that was not totally accurate nor complete and just controversial enough to stress some people out. Sorry I posted it.

[Vintage Copper 47]

Originally Posted by V8COOPMAN

Craig.......After a long career dealing mostly with the power distribution and UPS systems powering a huge air traffic control facility, I thought I understood a little bit about electricity, along with some reasonably-effective troubleshooting techniques to use when problems arose. I'll be darned, but your single paragraph above makes me realize just how dumb I must be with electrical stuff. I honestly never knew that 6v stuff only heats-up enough to make it easy to find the warm spots during a short.

One little tip here for ya none-the-less......there are SHORTS, and then there are the type of SHORTS that you haven't experienced....yet! Your little short between conductors (luckily) that you experienced powering both filaments only amounted to a temporary parallel circuit coming from a "like power". It's going to be an entirely different set of circumstances when that rotten cloth insulation allows a bare wire to touch any part of that grounded body. During a "dead short" situation like that, the conductor (wire) flows uncontrolled current from the battery to ground.........not unlike holding a wrench across both battery terminals. That relatively small wire will almost instantly glow red (more than WARM), at least all the way back to the high/low beam switch. That's why it's able to set that old dry cloth wiring (as well as any others in the harness) ablaze, releasing ugly amounts of black smoke. Of course, leaky fuel and grease can make it even more interesting. It happens so fast that you won't have a chance to get your door open to start looking for a wrench to undo the battery cable.

I'd really hate to see you lose your car based on your clear mis-conception of "6v auto electrics 101". A short to GROUND can really screw-up a guy's day. And when was the last time you tested those 69-year old circuit breakers? DD

When I initially purchased my 44 Chevy G506, I was driving home and was travelling on well-worn (read crappy) Interstate I-15 in Riverside, keeping in the far right (no. 4 lane for your highway patrol types) lane to avoid high speeder traffic when I hit a terrible pothole at 60 mph! All of a sudden smoke started coming into the cab.. I pulled over turning off the ignition before even coming to a stop.. it seemed that terrible bump was enough to bounce my coil wire from alongside the valve cover onto the thermostat housing instantly melting the insulation at that wire spot all the way to the fire wall..... My quick actions saved my truck from burning up; now I always have a fire extinguisher handy!
I added some extra wire to replace what burned and took it real careful til I got home safe...

[Ian NZ]

Originally Posted by corvette8n

These connectors have sealant in them, I consider this a better temporary fix.

https://www.superbrightleds.com/more...85bxoCo6fw_wcB

Corvette8n How do these connectors work do you still have to crimp the wires on them and what are they made out of, and do you have to heat them up with a heat gun to seal them?

[corvette8n]

Originally Posted by Ian NZ

Corvette8n How do these connectors work do you still have to crimp the wires on them and what are they made out of, and do you have to heat them up with a heat gun to seal them?

Yes Ian you do crimp them and heat them with a heat gun to seal them, They are like a normal crimp connection with a heat sensitive sealant that keeps the moisture out.

[Johnnydidd]

Old Henry, I think that's the fun of old cars is having a problem and fixing it. I would continue using, making sure the fuses are in good condition. I think you did a good job.