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I was wrong. Again. Not ignition switch!

RickB

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I had the bright idea to unplug the ignition, was going to take it out and see what was wrong with it.
I had charged up the battery and plugged everything back in and the fuel pump was ticking so I knew the circuit was still hot with the key off.
I unplugged the plastic connector pig tail to the ignition switch from the harness and... It all kept running.
Not the ignition switch after all.
Huh?
So I unplugged things up front again in order to turn everything off, now I am wondering what I did to cause all this.
It must have been me, I must have shorted something out or something when I was working under there.
This all started when I installed the new electric fan.
I pulled out the windscreen washer pump at the sane time because it wasn't working.
Wonder if I shorted something up in that corner by the master cylinders?
Now it's raining buckets outside and since I'm a "curbside mechanic" I'd either have to put on rain gear or not do it today.
Maybe I'll get a break.
Everything was fine until I put in the new fan, going to have to try and recall if I did anything else stupid.
 
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RickB

RickB

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I've got all week here in Vegas to think about this problem.

So as I see it here's my story - and the part that has me scratching my noggin:

If I turn the ignition key on the switched power relay energizes and feeds my 6 bank fuse box power.
If I turn the key off the relay stays energized, meaning the trigger wire is still hot.

Disconnecting the trigger wire (pull apart spade connection) de-energizes the relay, when I do this with the key off I can plug the relay right back in and it stays de-energized (that's the strange thing I am not wrapping my head around).
 
Last edited:

Pythias

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I could draw it for you, but it's harder to explain... .. , but when you turn on the hot lead, one side of one set of normally open contacts feeding back into the coil circuit of the relay... .. look up "latching" and "relay" and you can see it.... .. anyway.. check the wiring from the the coil side of the relay for your problem.
 
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RickB

RickB

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I plan to troubleshoot this by repeating the action that causes it and disconnecting a circuit at a time until it works correctly.
Since each has a fuse I can pull one at a time and repeat the key position and reset.
Yes Bill, I'm getting an unwanted latching effect from one of the circuits.
The electric fan is disconnected so that isn't it.
I won't be back in town until Friday night so I still have a few days to think about it.
One of the things powered through that fuse box is the fuel pump and since it has basically a small electric motor in it I suspect that may be feeding energy back and I will disconnect it first.
 

Sarastro

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This sounds a lot like what happened to me when I added a switched-power relay to my bugeye. It turned out that the alternator was powering the relay coil through the ignition lamp after I turned off the ign switch--it was enough current to keep the relay closed. My solution was to add a diode to the ignition-lamp circuit.

The circuit is here: https://www.nonlintec.com/sprite/electrical/wiring_complete.jpg

I used a 1N4006 diode, which should be readily available at any electronics place, especially since any 1N400x diode should be OK. Any diode that will handle at least 1 amp with a breakdown voltage of 100 volts or so should be fine. Be sure to observe the polarity--the wire on the diode closest to the stripe around the body (its cathode) goes to the alternator.
 
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RickB

RickB

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Thanks Steve,
This car has the Datsun motor and alternator so I don't know if that changes things related to your advice.
My bet is still on the fuel pump, I could be wrong but it will be easy to test since it's on it's own fuse.
 
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RickB

RickB

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Back at home again last night, it's a nice sunny day here in Snoqualmie so I've been digging into the electrical problem on my Midget.
Here's what I've done so far today:
Pulled fuses one at a time, turn key on and check voltage then turn key off and find trigger wire to the relay still hot.
Unplug trigger wire and plug back in, relay reset ready for next circuit.
Unfortunately this was the result with all the fuses.
Tried disconnecting the alternator too, same result.
Decided to replace my battery since I wanted to clean the terminals anyway.
No change.
Scratching the top of my head muttering "yeah, it's a puzzler..."

So having "all" the circuits disconnected there was still voltage on the white wire I am using to trigger the relay.
9.3VDC to be exact.
Key on, 12.7VDC
Key off, 9.3VDC

So using the decades of experience I have amassed actually working with low voltage circuits on things like high rise fire alarms, card key entry systems and such I did what anyone faced with such a dilemma might do - I started tugging on wires while watching the meter.
No change on almost all the wires.
Until I came to one cable, the voltage dropped to 5.2VDC when I tugged it.
I tugged it some more - now 3.1VDC.
I pulled it and followed it and found it's the wire to the stereo, which I installed before I rewired things and put in the two 6-gang fuse boxes.
Suffice to say that wiring is being replaced today.
Hopefully after I cut that loose and wire it up right my car will be back on the road - I'll post back here with either a big hooray or a tale of woe. :cool-new:
 

nomad

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Yeah Rick........my wife has this thing called a "shuffle" with all her tune's in it and its the size of a postage stamp.

Just saying........


Kurt.
 
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RickB

RickB

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I've seen those, but my radio has the ability to play from a memory card, from my phone, from AM and FM radio so I kind of like it and the speakers are big and loud enough that I can hear it with the top down at 75 on the freeway.

So here's the update:

I cut out the old cable and repeated key on, 12+ VDC Key off less than 1VDC.
Put all fuses back in, still good.
Started up - all good. Shut down, all off.
Hooked up radio properly and all still good.
Drove my grandson to the store and went shopping, drove home.
All good!!
WooHoo!!!
 
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RickB

RickB

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Today is another sunny autumn day in the Northwest.
I'll get out there in a bit and do a top down drive, there are a lot of nice back roads right around home and I mean to use some of them.
Who knows when our next sunny weekend will come, you have to drive when you get the weather and today is it.

For a PM on the relay issue this is what I know.

The radio was connected to an always on circuit and the ground for it was ganged together with the grounds for the fuel pump and the alternator / distributor.

I think something in the cable was causing impedance and there was (somehow) feedback to the relay, that's getting into electrical theory way beyond my understanding. Anyway eliminating that cable and connecting the radio to it's own fuse via one nice red hot wire and to a ground screw right by the radio itself solved the problem.
 
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RickB

RickB

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PM to the PM

Battery dead when I went out.
Only other thing I could imagine was to separate the two white wires I had going to trigger the relay for switched power devices.
Sure enough, one of them was keeping the relay triggered and the other was not.
Connecting the one larger white wire had the desired effect.
Cutting off the other kept things from staying on all the time.
I've no idea what the smaller white wire goes to as everything works fine without it.
 
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RickB

RickB

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WooHoo - started right up this morning, and my dash lights work now!
Maybe that smaller white wire was the 'gremlin circuit'.
 
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RickB

RickB

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Apparently one thing the small white wire was responsible for: Dash light suppression circuit

I've had dash lights all the way on my commute both yesterday morning and this morning!
First time in years I've had working dash lights!!
 

drooartz

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Apparently one thing the small white wire was responsible for: Dash light suppression circuit

Didn't realize that was a factory option. :grin:
 
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RickB

RickB

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Jim_Gruber

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Yeah that little switch on the left side of the column surround. Normally you can't hardly see Spridget dash lamps at all much less need to supress them.
 
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RickB

RickB

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Yeah that little switch on the left side of the column surround. Normally you can't hardly see Spridget dash lamps at all much less need to supress them.

Mine didn't come with that switch, it had the little round switch up above the speedo.
As soon as I got the car I pulled the wires from that switch and shorted them, but never had dependable dash lights until now!
Apparently that wire also functioned as the battery test circuit, as I'd have a flat battery every morning as long as it was connected!
 
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