Technical Here's a wierd wired one -

I've only got a few mins into this one but it's definitely different.
I haven't got to check the thing out thoroughly but this is what happens.

1. There is power coming into the ignition switch.
2. There's no power coming out of the ignition switch.
3. Plugged in a new ignition switch and the same problem.

Ok
WTF???
Check a couple other things with the new switch
Key off - has power into switch
Key On - kills power into switch as far up the harness as I can reach at the moment.

This one should be fun.
Was supposed to be quicky " can you change my ignition switch? "
I tried to get the guy on the road this morning so he could go have some fun.
Not gonna happen cuz I'm almost late for a cookout.

 

Sounds like a restriction in the supply to the key switch. Voltage drops because of the resistance. The resistance will cause heat. Turn on the switch and turn on some accessories and search for the hot spot.

 

Did you do a continuity test to only the switch to see if it's only there? Are there relay's involved with this vehicle? Edit - more things > Is it a bulk plug or individual wires placed individually? (I do not know if this car ran before or is freshly wired) I've seen bulk plugs where the wire has been placed into the wrong hole.

 

Aftermarket harness or OE? New problem or it never worked?

 

Test the switch on the bench if you can, isolate if it's a wiring or switch issue.

 

Its OEM harness,
Supposedly it Worked last year, which makes this is new problem. Newly Purchased with this problem. So all history is Deemed unreliable until I prove otherwise.

I will bench test the switch just to cross it off without assumptions but there are 2 different switches that didn't change the same issue.

My plan is to start with the battery- prove it worthy and work my way out from there with a volt meter

 

He brought it to the right guy. Happy Memorial Day.

 

Not sure if I understand correctly but if the power into the switch goes out when the key is turned to on but comes back when the key is off I would suspect a circuit breaker in the incoming line. Or, if the voltage at the switch is extremely low, it wouldn't take much of a load to draw it down to zero. In either case I would look for a dead short in one of the circuits coming out of the switch. I have done this by removing the plug and isolating the incoming power wire. Hook a test light to that incoming hot lead along with a jumper wire. Then go to each of the other wires in the harness and see which one causes the power to drop. If its a factory harness you should be able to find the circuit via Google by the color of the wire.

 

Hmmm;
I'm guessing here:
Could be a bad batch of switches, but that is somewhat unlikely.
It sounds like barely enough voltage to the switch to register, but no amps through.
Sounds like a damaged wire upstream of the switch(most of wires broken, but 1 wire in strand to allow voltage/ no amps through), or hidden corrosion downstream(anything from corrosion at connection to corrosion *inside* of wire to burned wire inside of insulation that doesn't show much outside). Problems I've run into chasing similar symptoms in the buses.
What happens if you jumper off the sw output to some load that (you know has a good ground) you could measure, to see if the upstream side is ok? Mouse-chewed wiring somewhere? This'll be interesting...
Marcus...

 

Jumper 12v to the power side if stuff works it's narrowed down. If it's in the power wire and there is a glass fuse I'd check the fuse contacts first.

 

Could be fun. Would seem to be a problem between the battery and the ignition switch unless it's losing the ground to your test equipment. First thing I would do is connect a wire from the battery to the ignition switch. I have a long 12 gauge wire with a 30 amp fuse, a large clap to connect to the battery on one end and a variety of terminals that can be plugged onto the other end. It can be a connection on the starter or starter solenoid depending on the system.

 

Have you checked the battery cables? I have seen a car with 12 volt showing all over the place, but when you try to blow the horn, turn on the lights, or hit the starter it goes to 0 volts. Turns out to be bad connection at battery or a bad connection at the starter. Even if they look good take them apart and clean them. Check the ground cable to frame connection also.

 

Since you say it is OEM wiring... What are we working on?

 

The bolt on style of battery cable ends were notorious for this.

 

Used to wiggle the firewall plug on my Chevelle to fix that problem. Finally wired the power lead around the plug.
So I'm guessing a corroded or maybe "load damaged" connection.

 

Glass fuses? Had one that was intermittent between the cap and the element, but I doubt the main feed would be fused from the factory. Next place I would go is to the bulkhead connector at the firewall if it is a GM product. D

Rich beat me to it!

 

You've got that right!

 

He must be at the cook out having a hamburger and a beer...

 

Is it a 60's Buick? They had ignition switch issue's up the *** and would do the same thing. They also were non interchange able with other GM switch's unless you wired it wire by wire minus the multi plug.

 

i am guessing bad /loose connection. firewall plug or failing fusible link.

 

I’ll dig into it more tomorrow

 

Battery voltage was only 11+ volts after full charge.
Hit it with a load and it fell to zero. Didn't think the needle on my guage could move that fast . Lol.

 

So much for the "customer is always right".

 

We will see soon see if there are other issues as well. But there's no sense in getting ahead of a bad battery.

What's funny,, really funny,, the seller made it a point to tell the buyer "the battery is good, fully charged" and of all the non relevant and completely unreliable information the new owner tryed to impart upon me, 3-4 times about the battery being good. SMH.

I told him my plan about starting at the battery and proving it worthy, he thought that would be silly since it's "Good"." The guy I bought it from charged it and it would go dead from a short in the ignition switch, must be a short someplace else" I called and told him "yep, the first short I found is something inside the battery, now you could take it back to the guy who couldn't fix it but that would be really silly." - you just fix it and I'll shut up.
Yeahhh!

 

Yes, you can't run a battery dead very many times before killing it. Overcharging it is just as bad.

 

If it the OEM harness it could be the plug in the firewall that is your problem. On my '65 for example I had power every where till I tried to start it then bababam. Nuthin. Switch tested out just fine, and what I ended up doing was bypassing the plug in the firewall for power to the switch then everything was groovy. Near as I could figure that firewall plug was too old and corroded to let enough amperage to pass.

 

Make sure that there is not a bad kink in the positive battery cable restricting the flow of electricities. My neighbors cousin's foot doctor had this exact same problem in his Pontiac Aztec. He had to take the whole cable out of the car and lay it on the driveway in the sun to warm it up so it would get soft enough that he could straighten it out. Once he got that nasty kink out he had great flow and pressure of his electricities. He said his tailgate opened faster and everything... so you should check that.

 

Yep, starting at the battery first was a smart move, always do the basics first. Go from easy to hard, do the easy stuff first. If it doesn't have a good battery there's no sense going any further until that's remedied.

 

i have had customers tell me they fully charged a battery and it was still dead "i had it on the charger the whole time i was at lunch"

 

1 trust but verify.

So far in all of my colorful travels across the world, seeing a battery with that immediate and massive of a voltage drop to zero was a first for me.

New Battery is on the way.