The Stovebolt Site Forums The Shop Area The Electrical Bay 1952 3100 Truck - Electrical Quandry

Hi Experts,

I've got a 1952 3100. Electrically speaking, it's pretty unmodified aside from a 12v battery. It was working just fine until a few days ago... now I can't get the starter to turn over. I thought the problem was the starter itself, but then realized that some electronics work, and some don't. So probably an electrical issue.

The headlights, brake light and dome light all work. The horn sounds like a dying duck.

The things that require the ignition key to be turned "on" are where the problem seems to be: nothing on the instrument panel seems to work (e.g. fuel gauge, temperature, etc.), and of course the floor starter doesn't cause the starter motor to turn over.

I've looked at the Chevy wiring diagram and couldn't figure out where fuses / breakers might be located.

I'd be extremely grateful for any ideas on fuses/circuit breakers, or other ways to diagnose and fix this little issue.

Thanks in advance for sharing your knowledge, and happy last days of 2021!

Billy

Ok, I’ll mention the obvious to get it out of the way “Battery”. Clean all the grounds and the terminals.

Thanks for mentioning that, Justhorsenround. I should have mentioned that in my original post- ensuring good/clean connections was the first thing I did. And the lights work well, so I figured the battery and its connections are working.

The original 1952 truck has a manually operated starter.
The circuit is basic.

1.)Ground connection (frame/engine to battery negative terminal of the battery)
2.)Battery
3.)Positive side of battery to terminal on manually operated switch (via foot operator linkage).
4.)Output of switch above to (internally) starter motor (starter motor ground is via the engine).

The starter motor should turn regardless of the ignition switch position, headlights, fuel gauge and other electrical components.
Concentrate on making the starter work.

Assuming you still have the stock wiring harnesses, the '52s still only had the 2 fuses on the firewall for the taillights and headlights. See the picture.

It sounds like your issues are mainly in the ignition switch. You should check to see if there's power at the ignition switch output terminal. The power for the instrument panel comes from that terminal.
As far as the foot operated starter switch, that's probably an issue with the switch itself. It's independent of the ignition switch.
The horn sounding like a dying duck is probably the horn motor itself.

Several helpers have pointed you to the problem.
1. Does not matter what electrical is working or not working because the starter motor gets direct full battery and starter is semi mechanically operated.
2. The issue you state is: "starter won't operate/no crank", (as opposed to a "no fire" issue).... so knowing how it all works tells you that it must be the battery, the starter, the button switch mounted on starter or cables. The only wiring involved is one positive battery cable and one negative battery cable. So now you know one of those items is bad.
3. Don't assume battery is good under a heavy load of a starter.
4. Don't assume cables and their clamps are good/tight/clean.
5. Don't assume starter is OK.
6. Don't assume button switch is OK.
7. No fuses or breakers involved in this.

Quick test is to jump the battery or use a temp battery from another vehicle. So try to eliminate the battery as the cause by using a known good battery....or have your battery tested under load by a trusted FLAPS or Shop.

The starter motor can draw 300 amps. This will break down a bad battery but then battery will be OK for small amp loads (bulbs/gauges). Also this amp load will break down loose, corroded, weak, broken, old cables, cable clamps and cable connections. Be sure the starter button mounted on top of the starter is still being pushed by the linkage. Report back.

Your battery needs 12.6V or near, at rest. It is the no. 1 suspect in this case.

Are we assuming that the necessary modifications have been made for 12V conversion? Spell that out for us. externally resisted Coil, starter button with side terminal, ballast, 6V starter..........What have you or anyone done since it last ran?

Thanks buoymaker, klhansen and bartamos for the great insight and suggestions. Really appreciate your input!

Knowing that the starter gets power directly from the battery is helpful. I'll start by getting the battery tested. Now that I think about it, the only thing that has changed since I last drove the truck (3 weeks ago) is a trickle charger - I added a trickle charger because I don't drive the truck much in the winter months. Now I'm wondering if the trickle charger damaged the battery, even though it's supposed to not overcharge batteries. I'm wondering if that's what happened, and now the battery isn't capable of producing the current for a starter motor, but is still able to illuminate lamps, etc.

I'll report back. Thanks again for your help,
Billy

While you have the battery out have a good look at the connector on the starter post (loose, corroded etc.).
Attached is something to give you an idea of what the mechanical switch looks like.

The starting motor itself makes a pretty good field expedient "battery tester". Turn on the headlights. Attach a voltmeter to the battery posts (not the cable terminals) and have someone step on the starter pedal. If the starter doesn't turn, but the voltage stays around 12V. and the headlights don't dim noticeably, you have a dirty connecdtion somewhere in the starter circuit- - - -either hot of ground. If the battery voltage bottoms out close to zero and the headlights go out or get very dim, the battery has an internal problem. After 15 seconds of cranking at normal speed (ignition switch off) the battery post voltage with the starter still turning should be above 9.5 volts. Don't use the starter motor as a tester repeatedly- - - - -let it cool down for 30 minutes or so after a couple of "tests".
Jerry

Update: I installed a brand new battery. I turned on the headlights and dome light and honked the horn - everything worked just fine. I then pushed the floor starter and could hear a faint "crackle" or "sizzle" coming from the battery. And the lights/horn wouldn't work after that. I wanted to see if I could replicate this issue... so I disconnected the battery, reconnected it a few minutes later. Again, the lights and horn all worked, but then I pushed the floor starter and hear another faint "crackle" sound and nothing electrical worked after that. No starter, and no lights/horn to follow.

Could this be the starter switch causing a short circuit when depressed? I inspected the starter and the "button" that is depressed by the floor starter linkage, and they both looked "normal", ie nothing caught my eye (take that for what it's worth).

Finally, I put a multimeter on the battery's hot *pole* and it read great. But when I put the multimeter on the hot cable (not pole), I got nothing. There seems to be something in the starter that shorts out and prevents current from flowing whenever the starter switch is activated.

Does this sound like a bad starter switch? If so, is there any way to address this without removing the starter itself? (I'm guessing not... but figured I'd cross my fingers and ask anyway).

Thanks in advance for your thoughts,
Billy

You probably have extremely corroded battery cable clamps. Get a battery terminal brush and get them shiny clean. One of those should be in every toolbox and used every time the cables are disconnected.

Scrape the inside of BOTH cable clamps until they're bright and shiny. If you don't have a tool like the one above, a sharp pocketknife blade works. Scrub the battery posts with a wire brush, then bolt the cables down tight. Then AND ONLY THEN, coat the cable clamps and battery posts with Vaseline, wheel bearing grease, or spray-on battery terminal protector. Some people slop on the anti-corrosion stuff and then install the cables, effectively creating an insulated connection.

No, "it looks good" or "the cables feel tight" is never a good substitute for cleaning ALL the connections. Once you're done at the battery, go to the other ends of the cables, unbolt them, and clean those connections thoroughly. If the ground cable isn't long enough to bolt it to the bell housing, the engine block, or a starter mounting bolt, go buy one that is!
Jerry

One last blow to the dead horse,,,,,has either of the battery cable ends been replaced with the type clamp that uses a bolt to clamp the battery cable to the end? If yes then disassemble and clean all the corrosion and reassemble. Or if the cable is long enough, just cut back to clean cable and reassemble.

Good Luck,

RonR

Just an update - I removed the starter and tested it using jumper cables and it worked great. Then looked more closely at the battery cable and noticed a faint crack where it connects to the battery terminal. I think it conducted enough current to work the lights / horn / etc, but couldn't support the current draw of the starter. So bought a new cable for $12 and all is well. Thanks again for everyone's troubleshooting advice - I learned a lot and appreciate it.
Billy

klhansen A ren't the 2 fuses tail and stop ?? headlights protected by thermal breaker on the switch.

Yes, you're right. My mistake.