1949 Electrical Problems

[Amigo 1]

To all early V8 electronic experts and knowledgeable informants:
My 49 was not indicating a positive charge except at high rpm. I had the generator tested and it proved satisfactory, so the voltage regulator was replaced. When the battery ground lead was attached it created an exceptionally large spark and serious ammeter discharge. Neither the starter switch nor headlights now work. The starter switch and wire to solenoid test ok. The old voltage regulator and new battery were installed without change. When the solenoid is jumpered from the battery contact to the starter switch post the engine turns over. The parking lights, horn, taillights, instrument lights and radio do work but not the headlights or starter switch. The fuse on the right of the circuit breaker which appears to go to the foot dimmer switch and dome light (which I don’t have) was blown and replaced. I have continuity and voltage to the circuit breaker and both fuses under the dashboard. I have tried to trace the circuits on the wiring schematic without much luck and am at a complete dead end. I’m pretty sure the new voltage regulator is defective and caused a massive short as I installed and polarized it according to the instructions, but the damage was already done. I’ve shorted the circuit somewhere but for the life of me I can’t ascertain where it is. Any advice or suggestions about the source of these problems and how to address them would be greatly appreciated.

[cas3]

any time a battery throws a big spark while hooking it up, you have a problem and it should be disconnected until you solve the problem. I would start disconnecting every circuit on the car one at a time, checking for spark at the battery each time until you get the one that stops the spark at the battery. Do not leave it hooked up, it could cause a fire.

[Amigo 1]

Thanks for the warning. When I changed out the voltage regulator there was no big spark. I can't figure out the connection between the failure of the starter switch and the headlights.

[Terry,OH]

Is your 49 a pick up, a truck or a car? From first glance the new regulator appears to be bad and shorted. Removing the new regulator may have removed the short circuit. and you appear to be left with some damage.
Start with one problem and trouble shoot that. The starter turns when the solenoid is jumpered so the circuit that picks up the solenoid or the solenoid itself may be bad.

[hueyhoolihan]

first thing i would do would be to buy one of these. they are of high quality and very legible a similar one for my '41 was indispensable in sorting out my wiring issues:

https://classiccarwiring.com/product...wiring-diagram

i suspect you own and know how to use a multimeter, as you've mentioned continuity...if not, then i would get one and learn how to use it.

continuity testing can be done with the battery disconnected. and should be all that's necessary to detect a short. i'd start with the headlights and search for convient and accessble places to place the multimeter's probes. they're even sharp enough to punch the a wire's insulation if necessary.

i wouldn't get too caught up in the voltage regulator issue, as its primary purpose is to maintain a constant output voltage from the generator or alternator. and only comes into play when the engine's running.

[Amigo 1]

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Thank you hueyhoolihan for suggesting a wiring diagram I can finally read! I do have a multimeter but was having difficulty reading the tiny schematic I have. I'll follow through on the headlight circuit. Thanks alot.

[Amigo 1]

Thanks, Terry, the car is a convertible. I'll follow up on the solenoid issue.

[hueyhoolihan]

Originally Posted by Amigo 1

Thank you hueyhoolihan for suggesting a wiring diagram I can finally read! I do have a multimeter but was having difficulty reading the tiny schematic I have. I'll follow through on the headlight circuit. Thanks alot.

those probes on multimeters are pretty sharp, at least they are on my multimeter, and can pierce the plastic sheath on a wire without too much trouble. i've been known to make use of them for that purpose to test continuity when accessibility to a bare wire is unavailable.

[Als48]

I also have (probed) wires with inaccessible ends by using sharp object such as a small nail or a heavy duty hatpin to check continuity or trouble shoot circuits. One could then seal the small hole if necessary, using silicone or some such.

Al Hook

[Amigo 1]

Good idea. thanks, Al.

[Bob C]

I have some probes that pierce the insulation, they work great.

[petehoovie]

Originally Posted by Bob C

I have some probes that pierce the insulation, they work great.

[leon bee]

The starter switch just makes a ground, right?

[koates]

Originally Posted by leon bee

The starter switch just makes a ground, right?

The starter switch supplies power to the starter motor terminal, NOT GROUND. Regards, Kevin.

[hueyhoolihan]

Originally Posted by leon bee

The starter switch just makes a ground, right?

if the "...starter switch..." in you post is what i call the "starter button", then...

i have a 1941 ford and two days ago i replaced my starter button (see link below). the housing of the starter button serves to ground the circuit to the starter solenoid (for on my '41 the entire metal dashboard is grounded.) and it, in turn, closes the circuit that runs directly from the battery to the starter motor, which pulls some serious amperage.

it looks as though the "starter button" on https://shoebox-central.com/1949-195...starter-button is the same as that pictured on the link below. compare pics on the links i've provided.

FYI, the starter button circuit does not involve the use of the ignition switch. so turning over the motor with the starter button can be done with or without the ignition switch in the "on" position. something one might want to keep in mind when working around it. best to disconnect the battery first.

https://www.dennis-carpenter.com/car...id=17182271752

[Amigo 1]

thank you everyone for your input.