Sonett community forum

intermittent electrical problem

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Hello fellow Sonett owners,

I have been having an intermittent electrical problem for about 4 months. All electrical goes dead, except the clock ticks. Have triple cleaned all grounds, cleaned all connectors, replaced the ignition switch. After cleaning everything 4 weeks ago, all has worked until today. Today I started engine, it died about a minute later (all electrical dead). Then electrical went on & I restarted it about 15 seconds later, backed car down driveway, died again! Then about 20 seconds later, electrical went back on & I restarted again, drove back into garage!

Any ideas ? I do not know what to do next ! What can kill all electrical ? Grounds are good, I always have 12v to the starter connection.

Mark

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Have you checked the output from your alternator? If the alternator is faulty, the engine running only on the battery will eventually stop the engine dead when it drains below a certain minimum. After resting a while, the battery may recover enough to start the engine again. The battery may have just enough current to run the clock but nothing else. Have you checked how charged up the battery is? If low voltage, this certainly points to the alternator.

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Alternator good, battery is new.

What is chance battery cable to starter intermittently looses conductivity? With the exception of enough voltage to run the clock? I could run a resistance test of this wire. Best I can figure ohm reading should be .025 +/-

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Hey, new to this thread. You say "all electrical dead". Do you mean that with ignition switch on ACC nothing works (except clock)? When you turn key to START engine does not turn over? Lights don't go on when engine not running? Yes?

If so, probably unlikely to involve engine electrical. Check ignition switch (you replaced it, I know, but wiring may be loose, etc) and light switch (depends on your wiring diagram). You should be able to first get the lights on without the engine running. Do you have a wiring diagram?

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See Digital Documentation for wiring diagrams

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When electrical is dead, nothing works, regardless of any position of the ignition switch, engine will not start. with the exception of the clock. When electrical is working, headlights, 4 way flashers & map light work with igition is OFF position, blinkers, horn, fan, etc work with igition is the accessory position. I do have Jack Ashcrafts electrical book & diagrams.

Because everything goes dead, the problem must be a main circuit, or ground?

Thanks, Mark

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It sounds like you have a bad wire somewhere in a primary circuit. The fact that you are not blowing fuses (correct?) suggests this is a ground fault not a 12v+ short. That fact that this is intermittent points to a frayed ground wire or  damaged/loose terminal connection. Also, not an engine electrical issue (starter, coil, alternator, etc.) since ignition OFF is impacted and ACC works when electric on. Obvious first thing to check is the battery ground wire connection at both terminal ends (loose, corroded, dirty, etc).  The clock works regardless because it has a working 12v+ connection directly to the battery (unswitched) as well as an unaffected 12v- ground wire separate from the rest of the electrical circuit.

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Quick primary ground test: when you experience a total electrical failure, put your voltmeter red lead on the positive + battery terminal and the voltmeter black lead somewhere else on the frame, not touching a fiberglass area, that has bare unpainted metal -- and not on the battery neg terminal either. You should read 12+v. If not you have a battery ground fault since current flow somehow fails between the negative battery terminal and the chassis. If you don't read 12v+ the problem is narrowed down a lot. It's either the battery ground cable itself or the connection on either end. If you do read 12v+ as outlined above with total electrical failure, then the problem is upstream from the battery and you have to look at all the other circuit grounds as a starting point.

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As stripe1 suggests above, if you get 12v+ then it's not a battery ground problem. In that case, I'd look at the battery-to-starter wire, and then the starter-to-ignition switch wires (generally 30 and 50 on wiring schematic); a third starter wire goes to the horn relay. Find the 30 wire (usually red). It goes from the starter to the ignition switch and then to the fuse panel. [note: There may be an intermediate connection between switch and the fuse panel that can come loose, too.] If this wire is bad it can cause a total electrical failure.

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Thank You for your sharing your knowledge!

Never had a blown fuse.

I will test the primary ground, am "patiently" waiting for total electrical failure!

According to my wiring diagram, the clock is connected to the #6 fuse (with 4-ways, cig lighter & map light). I confirmed it is by pulling #6 fuse-clock stops ticking. The clock is grounded separately with the dash lights.

So, when I have total electrical failure & clock ticks, I am getting power thru red wire #30.

(battery to starter to ignition to connector block to fuse block)

The battery is brand new & reads 12.5 volts, the ground wire is brand new with clean & di-electric connections at battery & chassis. (the ground is attached to one 5/16" bolt of the axle strap clamp)

This leads me to believe the problem is a ground fault. Is there any feasable way I could be losing ground thru the chassis ?

Again, I am "patiently" waiting for failure!

Mark