So my 3rd replacement ignition switch started tweeking out on me. Im tired of this. This is not a stock 914 so I decided to get an aftermarket switch. 10 bucks at Autozone and I have a switch that I doubt i will ever break.

So I pull the wiring which I have become so familar with and see that there are 6 prongs on it. One obviously ground(Black), One obviously power(red, thick), One keyed power (red, thinner), and one obviously starter(yellow).. But then I see 2 other small wires, a white, and a white/brown. Where do these suckers go? There is no accessory switch to the 914 so I doubt anything can go there, Are they the wires that are keyed power or say a relay? How do I wire this on a 4 prong switch??? I would think that the two smaller wires just go on keyed power, but I'd hate to do it and be wrong.


Thoughts?

Thanks all.

go here and find your year and wiring diagram.
Ground is usually brown.

I know its usually brown, but its obiously not in this case as there is no brown. Unless the starter ignition switch doesnt use a ground.


I was looking at the diagrams, but cant find "ignition" or similar anywhere on it. I've been looking at them for the past hour... Year is 73.

#26 on diagram two, "steering column switch"

If you have a 73, the logic circuit is under the passenger seat, or you need to at least look at that part of the diagram to account for the yellow wire.

Rich

In the center tunnel there is a wire, don't remember color,To the starter trace to under

dash, cut and install push button start. Use key for power and push

button for starter. This solved all my problems many years ago. I

even installed Hot Start Relay

The black wire is the ignition hot lead. the 2 small ones are most likely the key buzzer.

I saw 26 but there are to many wires on that diagram to make any sense.. Im looking at it now and see black, red, grey, red yellow in one small switch section on 26.. Which makes sense. But I dont see where the other 2 wires come into play...


I ran an ohm meter to all the wires to ground and black, yellow, small red and they all showed continuous to ground, which worries me. The 2 little wires and power didnt show continuous to ground.


So I am a little stumped, I thought I had it figured out till the point I checked ohm to all the wires..

OK so lets put this down.

NEW SWITCH -------- 914
Battery :: Thick Red
Ignition :: Black, Thin red
Accessory ::
Starter :: Yellow

You cannot ohm out a complete circuit. By that I mean; The yellow wire goes to the starter, through the solenoid which is grounded. Same with the coil and so on. You need to open the connection at each device in order not to read ground. You will be fine.
Red= power into switch
red= switched power on
Black= switched ignition power
Yellow=starter

Really all you need. You are thinking too hard...

No real Accessory position on old German cars. The thin red is power to the headlights and stuff. Black is power to fuse 7 and coil.

Doesn't one wire go from the switch to the headlight relay?

So what your saying is im right?

I just tested it and it seems right.

Yep

Better to leave the small ones off. Hopefully you have not blown anything up yet.

Heavy Red is Battery IN, smaller Red looks like ACCY power OUT (to 15 on the light switch).

Black is 15, ignition OUT.

The others are most likely the buzzer contacts and the power for the parking lights. Remember, the one-side parking light only works when the key is OFF. That would be a gray wire. A contact that supplies power when you turn the key off is not something a generic switch is going to give you.

Man, the '73 diagram is the most F'd up of all the 914 diagrams! Steering column switch indeed. It has the turn signals and wiper switch AND ignition all in there, it's no wonder they went with the current flow type diagrams in '74! Both the '71 and '74 diagrams are easier to follow...

MMMMkay... On my testing zone I had the little red wire hooked up to the accessory position, the black wire to ignition and yellow to starter.. Then I put the little red wire to ignition with the black wire and bolted it all in.. Now the starter is kicking when i turn the key to the ON position....


I am stumped. I am going to put the red wire to the ACC position again and see what happens. when I bolt it up..

So I disconnected the yellow wire and tried the key again, no starter kicking over so I verified that the yellow wire is starter... Now im really pissed off. This lovely little ignition switch is now being a piece of crap on me... Im going to move the red wire to accessory and see what that does. I dont see WHY it should do ANYTHING...

WTF

I disconnect the switch and check it out. Looks great, functions VIA the ohm meter as normal.

THEN I check the ohm of the hot wire... (battery disconnected) it states its hitting ground..

AHHHHHHHHH I am SO pissed. I cant think straight. So im thinking frayed wire, bla bla bla, Somehow I think the wire must have frayed when I moved it 6" carefully....

This is NOT what I want right now and I have no clue where to start.

Did I mention I am pissed?

its not hitting "ground" its conducting thru the battery to the neg that is connected to grnd. thats ok. your talk the big red right?

did you dx the batt with the neg or the pos

It sounds like you are trying to connect the aftermarket switch up correctly.

If you look at 26 on the diagram the middle 5 terminal are the ignition/start switch.
15 - 2 black wire is ignition power out
1 of the wires goes to the fuse panel (fuse 9) and then to the eng comp fuse/relay panel
1 of the wires goes to the logic relay under the passenger seat
X - Red wire is accessory power out
P - Gray wire is power out with key off
30 - Big Red wire is power in from the battery
50 - Big yellow is starter power out

As the key is turned first power is cut off from the gray wire then when the key reaches the "on" position power is supplied to both the 15 and X terminals.
As the key is turned past "on" to the "start" position power is cut off from the X terminal to reduce the electrical load so more power is available to the starter and ignition.

If you are eating up stock switches maybe you need to put relays on the accessory circuit or check to make sure you do not have excess load tied to the ignition circuit. Often extras (stereo, amps, fog lights, etc) get connected to the first switched power found. There could be more load on the switch than is can handle.

Good Luck
Jim

Disconnected the battery at the negative terminal. I am talking about the big red cable, I dont see how it would hold Ohms with ground if the battery is not connected to ground. IMHO I see that as a short.

Jim, What is happening with the stock switches is I can only find the aftermarket one's and they fail as are extremely common with them since they are made extremely poorly. I have no accessories in my vehicle. No horn, no radio, no fuel injection. Just lights, distributor and fuel pump.

Your explination makes perfect sense. However I dont have a grey wire so I guess I dont have to worry about that ?

I am still stumped as everything mentioned will lead me to wire the switch the exact same way, which I know will result in the same problem (Starter getting power when keyed on.. Which is not the switch's falt as I see from testing.)

As I mentioned earlier, ALL wires show continuity with the ohm meter to each other. I have NO idea how, or why, but I feel that that is WRONG. Any thoughts on this subject would be greatly appreciated.

Again this is tested with negative battery terminal disconnected.

I've probably installed a couple of hundred aftermarket ignition switches, and maybe had a dozen premature failures, mostly on Audis with a well known poorly designed load on the switch. I think your failures are indicative of other issues, not switch quality problems. As for the generic aftermarket "universal" switch installation, every one I've ever installed (and I've experienced about a 30% premature failure rate) has had the terminals clearly embossed on the back of the switch (like "batt", 'ign", "acc", "start", and such. Hard to mix those up, if you think about it.

Now, for the krustiness ........ Why don't you just fix the underlying problem? Get some help and support from the folks here? It's not like you live in the Australian outback or the wilds of Northern Canada.

The Cap'n

Captn,

Yes the aftermarket switch is clearly labeled and tests correctly with an Ohm.

Capn, what underlying problem might that be? The switches that have failed on me are due to the actual switch and I am sure of it. The wiring has not changed, and yet a replacement of the switch fixes the problem immediately. The problem being that with the turn of the key to the on position they would only transfer a small portion of the voltage (as checked with my volt meter in dash) or would not transfer voltage while cranking, or both, and the key had to be in a specific position in the cranking position to actually transfer volts to more than just the starter. Yesterday when starting the car it wouldnt show any volts and would crank slow, waited 5 minutes, jiggled the key, and it started without a problem (The start of the old problem I had been having). At this point I said NO MORE and bought an aftermarket switch.


Again, aftermarket switch checks out. My wiring is now the issue as I have said before many times in this thread. I am going to check for frayed wiring and see whats going on, however if anyone has any suggestions for where to start, I would appreciate it.

This car is getting very close to a full rewire.

pull the wire from the battery POSOTIVE terminal...remove it from the bundle of other wires so its hanging in the air ALONE.

You could be seeing a dead short in your battery...and that happens when you overcharge a battery...
Both the voltage regulators can do this as well as a cheap battery charger...or a super charge 50 amp charger.

Then ohm it again.

Rich

I'll give it a test tonight. Battery is kicking 12.3 volts as of last night. I havent had the battery on a charger in a while. Optima Red battery, 1 year old, barely any miles (maybe 2 charges on a charger, it held a charge really well).

cant ohm the red wire while its connected to the battery...it will give a false reading.

Never ohm a wire that is connected to anything.
Bare unplugged ends is the only way to be sure.

For your switch.
You will see power on the large red lead from the battery.
Yellow goes to the starter (via the logic relay under the passenger seat)
Pull the passenger seat out and take a look....that may really be the underlying issue. Its a one year only thing...

If that logic circuit was removed (looks like a relay) then you need to make sure the two yellow wires are connected or you wont have a starter circuit...a dirty or weak connection there will never stop giving you grief.

RIch

Well I can say that that relay is LONG gone... Seats are modified, but I have access to the wiring in that area, but I dont remember seeing any wiring going to the seat (Been a while since I wired up that area).

Two yellow wires. I'll give those a look in a little.

Good info on the red wire, That was freaking me out. I'll disconnect the + and ohm again.

Try these things. (1) Sub in a different battery. Optimas don't like to sit. I've seen multiple failures on cars that sat for long periods. (2) Your description of the importance of position leads me to suspect the steering lock assembly. I'm sure someone here can loan you one for testing purposes. Look for movement of the tab corresponding with the movement of the key. (3) Check the voltage FROM the battery at rest and then with the key in the start position. If the wire from the battery to the switch and fuse panel is bad, it can measure OK and fail to carry battery voltage when loaded. If the cable to the starter is bad, same thing. We've heard of 911s with the battery cable unable to carry 12+ volts to the starter. Pretty common, actually, and that sucker is REALLY hard to replace. (4) Verify your grounds UNDER LOAD!

Report back.

The Cap'n

reminds me of my plow truck...a dual battery diesel with a starter that has more power than a type4 motor...

I replaced the starter (twice), ignition switch, starter relay...both batteries.
When I finally replaces the super large battery cables ($200 bucks) it spins like a top...

Battery cables do get less than useful over the span of 40 years.

Rich

Rick,

Cables are under 5 years old. Starter has direct ground to negative battery post on body.

The issue here is not with cranking, Starter cranks wonderfully and has this whole time. Issue has been not getting full voltage to electronics while cranking or with key on (This was with stock ignition, which I am ditching and NOT going back to).

Capn, I'll try these things. Thanks!

Pulled the positive cable from the battery and separated the wires. It is still continuos with ground..... So, yay.... Hours of toil ahead...

Well, yeah, an ohmmeter WILL show a short to ground if ANY load is on the other end of the cable. Do you have a radio with a clock lead connected to permanent power? Or a power amp? Those will look like a short to ground. Do you have a light turned on, or anything else that's on? Do you get a small spark when touching the wire back to the battery terminal? ANYTHING on will look like a short to an ohmmeter.

Pull fuses or disconnect the red wires till you are sure that you can see both ends of the same wire hanging in air, THEN if you STILL read a short to ground it will be time to search for the short or replace the wire.

The wires have to be disconnected at BOTH ends for a resistance test (ohms). What you want is a voltage drop test, first with no load, then under load.

The Cap'n

Edit: A voltage drop test is done by probing the wire at its source, in this case the battery (with the meter ground connected to the body), and then at the end user, or anywhere in between. Unloaded, .1V is allowable, .5v is NOT. If you have a drop, then you need to fix the wire or its connections. Loaded, like on the starter cable with the starter engaged, there's a little more leeway because of the magnitude of the current draw.

914Mike,

I see. That makes sense.

Actually there is nothing that stays on (Radio disconnected completely, no clock, no amplifiers), but im sure one of the light relays has constant on, so that makes sense that there would be continuity there now. And no I actually dont get any sparks when connecting or disconnecting the battery, there is really very little drain.

This short thing just scared me, as I really dont want an electrical fire if I can help it..

I've been doing this on my own, I'll ask my dad for some help tonight, he has way more knowledge and practical experience in wiring than I do..

Andyrew,
Did you remove the positive battery terminal each time you changed out the ignition switch? If so, you may have one or more of the large red wires at the positive battery terminal going bad, ( as in the connector or wire right at the connector). Each time you remove the terminal, you disturb the wires and cause a good connection that deteriorates over time. One of these red wires goes to the switch, one to fuse panel, and two to the relay board.
It is an easy thing to check if you haven't already.
Tom

Tom,

No, I didnt disconnect the positive battery terminal. The time I did durring lunch today was the first time it has been disconnected in years.

I typically disconnect the negative battery terminal (However in the case of the ignition switch installs I didnt bother, until yesterday when I was dealing with raw wires).

At any rate, I have already repaired the positive battery collection of wires. (Not the prettiest, but its very functional)

For shits and giggles i installed the wiring again as mentioned the way i should and it works. I dont know why but it does. Im going to mount it and see if maybe the grounding of the body makes a difference. Maybe i was out of my head last night and swapped the little red and yellow?? Donno. Well see.

Test the continuity of your switch (ohm out)

Power terminal to all others with key out= should have an open circuit

Turn key to run position= power to ignition shold be less than 1 ohm. power to starter should be open circuit.

Turn key to start position= power to start should be less than 1 ohm, power to ignition should be lees than 1 ohm.

Ignition terminal must be "hot while cranking" or the car will not start. If it not then you do not have the correct ignition terminal.

Mike, this is what i tested last night (multiple times), the new switch wprked perfectly.

Mike, this is what i tested last night (multiple times), the new switch wprked perfectly.

Ooook.. I just tightened the bolts down but left the wires hanging in the same location, same issue, starter cranked. So then i loosened the bolts a little so there was still contact but it was just like my test position, no issue, theb tightened it halfway and it jumps back and firth between wanting to start and not( keep ib mind there is plenty of contact between the wires and the switch at all these times, this would be an issue with the switch).


Now im going to remove the switch and tighten the bolts all the way down and check it with an ohm meter

Have you tried to hot wire your car? Just to see if it will start? At least it will let you know for sure the ignition switch is bad.

Defective. The starter terminal worked itself loose and causes the issue

Damn Chinese parts...

Mike, yes i test all functions of the key switch when im doing the keyed testing.

New switch installed, tests good, took it easy on tightening. Everything seems just fine!

Drove to work!

Glad its fixed

Andy,

Glad you got your car sorted; the OEM's are available. Put one in my car last week and all problems starting ended.


Joe

Joe, where did you get your OEM switch? Porsche?