TheSamba.com :: View topic - Bad Ignition Switch? or a larger electrical issue perhaps?

Tue Sep 12, 2023 2:58 pm

So here's my new discovered problem from the safety and comfort of inside the garage. I went to do a pre-start inspection of (newly plumbed fuel setup A-Z). Which means that I turned the car ON not over, and turned on my switch to fuel pump. And fuel pump did not turn on as it previously had minutes prior (no sound or light indicating power) I began chasing down a bad ground and checking power wire connections. and suddenly I smell electrical burning smell look up from under car and looked to see smoke filling the backside of my plastic cover to all wires at dash.

after turning of key and disconnecting the battery, I removed cover to find the black ignition wire coming from key cylinder to fuse circuit #2 fried and sheath crispy and crinkled. YET the 8a fuse on this circuit did not blow!

So I could use a hand on with ideas as to figuring out how to pinpoint and correct any issues.

Hopefully all is clear, Thanks in advance.

Tue Sep 12, 2023 3:40 pm

vintagevoudoo wrote: … after turning of key and disconnecting the battery, I removed cover to find the black ignition wire coming from key cylinder to fuse circuit #2 fried and sheath crispy and crinkled. YET the 8a fuse on this circuit did not blow!
You didn’t ID the model year of your Beetle, but it really doesn’t matter. Since it was fuse #2 powered by the ignition switch wire I’m gonna guess your Beetle is a ‘68-‘70 model year?

The error in your thinking is that the black (#15) ignition switch wire connection powers the ignition switch from the fuse box. It is actually the opposite. The ignition switch is the power source and that black wire you found melted is the source of power to the fuse box. That black wire connects to the unprotected side of the fuse box. If any part of this wire touches ground the ignition switch output is directly shorted to ground and there are no fuses (from the factory) between the battery and this point to protect the circuit.

Things for you to check…
How much of that black wire has melted? Can you splice in a new segment of black wire to replace the melted bits? It looks like there is a splice in this black wire and only the portion after the splice melted? This could mean the wire gauge after the splice was a smaller wire than the wire before the splice? If this is the case it could explain why the wire melted? It wasn’t the correct gauge? The stock ignition switch wire was 1.5mm^2 which is around 15AWG (between 14AWG and 16AWG). If replacing this wire go with 14AWG.

Between the battery and this black ignition switch wire is the electrical contacts of the ignition switch. Have these been compromised? Have the plastic parts of the ignition switch melted?

Was the short actually here at the fuse box? Could the short have been somewhere else? The common place to short out the unprotected part of the ignition switch is at the ignition coil. The black wire that powers the ignition switch comes from the same side of the fuse box. A short at the ignition coil end of this wire will short the entire circuit from the ignition switch to the coil. This is a much harder wire to replace.

The power source for the ignition switch is the red (#30) wire coming from the headlight switch. This is a thicker wire so can sustain the heat better but may also be compromised. Check the red wire from the headlight switch to the ignition switch. Also check the red wire that runs from the VR to the headlight switch. All wires from the battery to the ignition switch are not protected by any fuse.

What can you do to protect yourself from the same thing in the future?
Add a 16A~20A inline fuse in this black (#15) wire between the ignition switch and the fuse box. This will protect the circuit.
Additionally, you can add a 60A circuit breaker in the wire from the battery to the VR. This can protect the red #30 wire running to the headlight switch from direct shorts to ground.

Tue Sep 12, 2023 4:10 pm

Excellent info. Mine is a '69 with exposed metal contacts. So here are my thoughts. I just finished reading a post in which Cusser mentions adding the inline fuse between terminal end and fusebox, so that is an absolute must add. I also read a post in which you Ashman mentioned the VW updated 72+ ignition switch with male terminal ends. So for me this seems to be an excellent time to "future proof and upgrade to this style provided the ignition cylinder barrel has enough space/depth to allow it. I've located one close by and I am in route to pick it up.

I sure do hope that I didn't smoke my coil or magna spark 2 distributor.

as seen in the pic the wire sheath is crispy roughly halfway up from the terminal end but does not enter into the loom going into or towards the keyed ignition. I'll know more once I have it apart.

I will check the head light switch to ensure / verify there is no grounding or contact from the #30 red power wire from headlight switch to body etc.

I swear this headlight switch design has been the Bane of my existence as I hate it for this very reason. I am looking to upgrade this somehow with a variety of switches to remove/prevent such hazards in the future.

I'll know more with further inspection and parts in hand. I'll update this post with pics of things as they develop.

Thanks for the gameplan. Off to see the parts wizard and then down the wire road to recovery.

Tue Sep 12, 2023 8:54 pm

So I found the culprit to be a spade from my positive side of the coil. It was touching/grounding out on the heat sink of the coil therefore NUKED my ignition switch.

As of now the plan is to carry out the "upgrades" mentioned above in addition I will run a small 3" extension wire from the positive side of coil to a plastic covered T spade connector to eliminate accidental touches then rubber cap (w/vac hose) any exposed male spades from both positive and negative sides of the coil.

ran out of time so it'll have to wait til the weekend, but now I have time to oder a few things and have those in hand next time Im working on it.

I continue to learn more and more as I spend time working on my bug.

Tue Sep 12, 2023 8:59 pm

Now you know why I have in-line fuses for that circuit on both my VWs. Right after the fuse box, goes to the #15 wire back to coil positive terminal.

Wed Sep 13, 2023 8:16 pm

vintagevoudoo wrote: So I found the culprit to be a spade from my positive side of the coil. It was touching/grounding out on the heat sink of the coil therefore NUKED my ignition switch.
This is bad... possibly worse than you know.
The ignition coil #15 black wire starts at the ignition switch; goes to the unprotected side of the fuse box and then runs all the way to the ignition coil #15 (+) terminal with no breaks. If the ignition switch to fuse box wire melted when the coil wire shorted... it is very likely the entire length of the wire between the fuse box and the ignition coil has been compromised as well. You need to inspect this wire INSIDE the main harness.

When a wire gets so hot that it starts to melt the insulation in segments of the wire that is exposed to open air (where it cools the best) the sections of the wire contained inside a harness will heat up sooner and start to melt the insulation of neighboring wires. I suspect other wires in your main harness (running from the dash to the engine compartment) have started to melt. Inspect and find out. Split open the harness running along the left side heater channel and inspect the wires.
In worse cases, multiple wires in the main harness is compromised and the entire harness will need to be replaced (they do sell just the main harness for just such cases).
Best case... you may only need to replace the black #15 wire only; or maybe just sub-sections of it. But if the black wire inside the harness has melted in the harness you don't want to continue using it. Run a new wire for the whole length.

Mon Sep 18, 2023 6:23 pm

@ashman40

makes sense. I am inspecting now as I pulled the ignition switch. and quick update. I bought the 72+ ignitions switch with the male spade ends. Well turns out I can not fit it into the lock cylinder as the position of the locking pins and the center tumbler are not clocked exactly the same and because it does not line up exactly it will seat into the cylinder so this is a bummer.

A curious note what is "p" (gray clipped wire) for? It can be seen in the photo uploaded and should display below. I would like to know if this is the mystery gray wire that is found and unused coming from the turn signal wiring. I am interested to know if these to are ultimately connected and if I am missing or losing some function by these two gray wires not being connected.

@cusser what size fuse 8a? I am going to use a 7.5a ATM style fuse. But absolutely, ya don't know what ya don't know, well now I know and I know that knowing is half the battle, haha! yeah now I am stuck til local VW shop opens in the morning to pick up switch, but now I plug away with prepping my inline fuse as well as wire harness inspection, gulp!

Tue Sep 19, 2023 6:38 am

vintagevoudoo wrote:
@cusser what size fuse 8a? I am going to use a 7.5a ATM style fuse. But absolutely, ya don't know what ya don't know, well now I know and I know that knowing is half the battle, haha! yeah now I am stuck til local VW shop opens in the morning to pick up switch, but now I plug away with prepping my inline fuse as well as wire harness inspection, gulp!

7.5 or 8 amp should be fine to the coil, as would be 10-amp.

Tue Sep 19, 2023 11:08 am

i have no idea what law of electricity is involved but when you ground out a hot lead (like the one to the coil) the wire overheats and starts to burn off the insulation at both ends and works its way to the middle...so 90 % of the time the damage is isolated to the ends and the wire inside the harness is fine...but check it anyway...all depends how long it was grounded out....iirc all the replacement switches came with that extra grey wire...always assumed it was to power up citylights or some other feature US cars didnt use...directional switches had extra wires on them too...just for another thing i noticed, that big washer you have rigged to hold in the fusebox looks awful close to the electrical contacts so make sure that doesnt become your next issue

Tue Sep 19, 2023 1:10 pm

The VW ignition switch came with two extra wires depending on the model year and/or if the switch is aftermarket or OE.

The OE ignition switch that came in my '71 steering column had a single grey wire which was grounded while the key was inserted. This serves as a ground for the door/key buzzer that sounds when the key is in the ignition and the door is opened.

The aftermarket ignition switch I purchased came with a solid grey wire that had 12v+ while the key was removed. This would be an ideal trigger for an alarm.
The aftermarket switch came with an extra brown/blue wire which is grounded when the key is inserted. This would be the same as the earlier grey wire in the OE switch.

I'm going to guess your grey wire is the ground wire not the power wire.

Wed Sep 20, 2023 2:34 pm

@volksworld & @ashman40 this is news to my ears, as I have 1. always wanted to know 2. I've been wanting to either add and alarm or a key chime. so once out I figure which I have I can use it accordingly.

Also I just checked the wires mid harness section and to @volksworld's point only the ends have shown signs of excessive heat. I did check continuity and even started the vehicle (I did buy an new coil-a precaution) car started and I began to prep to get back to my scheduled and long delay carb tuning when my battery was to low to continue cranking/starting so now I am off to see the Autozone to get it quick charged.

I did note however that I no longer have red lights for either gen (I have alternator) or oil pressure. I read a post but it applied to 71+ super's on 11 +12 fuse. I do not have any blown fuses and pulled 1, 2, and 9, 10. I found a blown bulb for I thing oil pressure but replaced both, but another wrench in the progress is I now have a bad battery, so not the research begins for a new one, antigravity battery, anyone, anyone, anyone?

to be continued

Any thoughts on what this could be?

Thu Sep 21, 2023 8:56 am

vintagevoudoo wrote: @volksworld & @ashman40 this is news to my ears, as I have 1. always wanted to know 2. I've been wanting to either add and alarm or a key chime. so once out I figure which I have I can use it accordingly.
The powered wire from the ignition switch when the key is turned OFF was not there on my OE ignition switch. It was there on the aftermarket switch. So clearly the existence of the circuit depends on which switch you have.

vintagevoudoo wrote: ... my battery was to low to continue cranking/starting so now I am off to see the Autozone to get it quick charged.
Be aware that discharging a lead-acid battery multiple times will cause the battery to go bad sooner. If your battery is over 5yrs old consider buying a new one.

vintagevoudoo wrote: I did note however that I no longer have red lights for either gen (I have alternator) or oil pressure. I read a post but it applied to 71+ super's on 11 +12 fuse. I do not have any blown fuses and pulled 1, 2, and 9, 10.
In '69 the black wire that powers the 3 bottom indicator lamps of the speedometer comes from the INPUT side of fuse #2. This means even removing the #2 fuse should not disrupt current flow to the indicator lamps.

Test for power at the fuse, on the black wire running to the speedometer and at the 3-bulb holders at the bottom of the speedometer.

Thu Sep 21, 2023 9:56 am

@ashman40, Yeah my battery has been discharged and bunch within the last few months and 5-6yrs olds so I guess I got my money's worth.

I just came up from the rabbit hole of battery research and making my purchase today. And I will check to make sure the black wire powering the three bulbs is in good condition and not disconnected.