Whats wrong with our ignition switches?, What do we know? Options

[JeffBowlsby]

"Ignition switches are junk"

Regularly hear this and similar consternation.

I have continuously owned one or more 914s since 1998...think I have replaced only 1 ignition switches over that time, in one car. My current primary car I have had for over twenty years, still on the original switch as far as I know, I have not replaced it during my ownership.

None my cars have ever had the added relay although I'm not against it.

For those switches removed and in other key ignition switches I have opened up, what I see is part of the housing is cracked in similar locations. Maybe from years of torquing the key over? Not sure. I don't see melted housings (believe they are nylon), no smoke residue or anything out of line, just the cracked housing. Suspect the cracked housing causes some internal misalignment of the internal contacts...i.e. the switch goes bad and needs replacement.

I am thinking the problem is the switch housings that break, not anything to do with excessive current flow through the switch.

Educate me please.

[Ishley]

I've had several go out in 2 years...

The issues I have seen with the new ones is that something breaks inside the switch. The plastic is not strong enough. I am not seeing any electrical issue... it's a mechanical problem... and once it internally fails... it won't make connection to engage the starter.

I spoke to George at Auto Atlanta to complain about it and I mentioned how many I've seen on this forum and others all having the same problem. He told me he rarely sees any come back... he had numbers... and his data showed that indeed very few come back. I suspect that the issue is the cost of shipping. If you order from anyone now days it cost $10 to get it... another $10 to return it and if they ship it free... you wait 2 weeks to get it. I'm impatient... and honestly I'd just go to PMB or somewhere else...for a $16 switch. They at least ship faster then AA. I've ordered from several suppliers... and keep 2 on the shelf. They are all the same.

Since non of our suppliers are standing up and demanding better quality... and with only one manufacturer... nothing is going to change. Were doomed by a monopoly. I do plan to install a secondary push button switch in the engine bay as a a backup if I get stuck on the road.

[tomeric914]

I spoke to George at Auto Atlanta to complain about it and I mentioned how many I've seen on this forum and others all having the same problem. He told me he rarely sees any come back...

There are reasons many of us don't go back to AA.

About 10 years ago, my switch failed. I was on a business trip in Atlanta and stopped by AA to pick up a switch. Spoke to their parts guy who said that the trick was to shim the switch with a small piece of paper. Paid $30

Flew home and installed the switch and it didn't work.

Ordered a new switch off evilBay for $3 plus $6 shipping. When it arrived, I found that it was the identical switch in an identical marked box as the AA switch. Installed that switch and it didn't work either.

Final solution was to purchase a used original German switch from a VW Bug off evilBay for $10. That switch has been in place with no issues for the last 10+ years.

My original switch was cracked and worn and just not making contact.

For those that have melted switches, one thing that hasn't been mentioned is what happens under continuous cranking, when the engine won't start. While the amp draw may by ~25 amps on a fully charged battery, keep in mind that the amps will go up as the volts go down.

[Superhawk996]

For those that have melted switches, one thing that hasn't been mentioned is what happens under continuous cranking, when the engine won't start. While the amp draw may by ~25 amps on a fully charged battery, keep in mind that the amps will go up as the volts go down.

This isn’t the case.

@tomeric914 this response isn’t directed at you personally. I mean no offense.

These sorts of misunderstandings about automotive electrical components and wiring are extremely common. This misunderstanding of electricity is a large portion of why these ignition switches get blamed for problems when the problem in fact lies elsewhere.

Ohms law applies: current draw = voltage divided by resistance (I=V/R). If the supply voltage drops . . . current drops. The solenoid is basically a fixed DC resistance and remains constant.

Melting is a function of increased resistance. Usually from corrosion or loose connections that leads to excessive power (ie heat) being created at the switch contacts, the spade wiring connection to the switch, or within the yellow solenoid wiring itself.

Power = current squared times resistance (P=I^2 * R). In this case, where normal current draw is about 25 amps, it only takes a tiny increase in resistance across a set of electrical contacts or within wiring to generate lots of heat.

Example: let’s say a bit of corrosion builds up and increases the resistance by a minuscule 0.05 ohms which you can’t even measure with a regular multi-meter.

Power = 25*25*0.05 =31.25 watts of heat. How much heat is 31 watts? As a reference, a pencil soldiering iron is typically 25 - 40 watts and will burn you in an instant if you touch the tip and will melt plastics with no problem.

[tomeric914]

@tomeric914 this response isn’t directed at you personally. I mean no offense.

None taken! That was bad on my part. Where my thought (and likely others go) is from power transmission, where a smaller wire at higher voltage can support more power where P=I*V. You are 100% correct that I=V/R where amperage will reduce proportionate to the voltage as long as resistance remains the same. One could argue that resistance can increase as the temperature of the components increases, but that isn't where I was going. Thank you for the correction.

[Superhawk996]

@tomeric914 this response isn’t directed at you personally. I mean no offense.

None taken! That was bad on my part. Where my thought (and likely others go) is from power transmission, where a smaller wire at higher voltage can support more power where P=I*V.

(IMG:style_emoticons/default/beerchug.gif) it was a good discussion to have. And you’re correct that certain loads like an AC induction motor can be approximated as a constant power load. Just not applicable to automotive (at least of our 914’s vintage).