Installing a starter buttong inside the car, but there are three red wires coming out of the ignition connector - which is the hot feed that gets connected to the other spade terminal?

From the wiring diagram

15 - which also has a black wire coming out of the same terminal, both going to the fuse panel
30 - goes back to the starter
X - on the diagram it goes to a square with the number 49 in it (I have no idea what that stands for)

I already have the yellow wire from the solenoid connected and thought the power would be X, but I think I guessed wrong.

Thanks!!!

What you want is to connect the new starter button to the switched power (black wire) out of the ignition switch and connect it to the yellow wire that goes back to the starter. Make sure the button you're using can handle the current required to operate the starter solenoid, which is going to be fairly hefty. Figure about 5A, or about 65W.

If you connect to a red (battery+) wire instead of a black wire, you'll be able to use the starter button to turn the engine over with the ignition off. There are a cluster of battery power wires near the fusebox that's a convenient place to tap unswitched power.

So I want the black wire coming out of 30 that goes to the fuse panel?

Got a sealed 60 amp button at Kragen - that should do the trick.

30 is battery power, 15 is keyed power, and 51 is the wire to the solenoid. Same on all German cars.

Well, I just connected the black wire out of 30 to the starter button, and now I have nothing. Nothing when I turn the ignition on, and nothing when I push the button. WTF am I missing here?

First, someone has their numbers screwed up. If 30 is battery power, it should have a red wire, not a black wire, attached to it. If it has a black wire, it's switched power, not battery power.

The way the circuit goes is red wire from battery + to ignition switch, black wire from ignition switch to many places that require switched power (including the coil), yellow wire to the starter. To have a starter button, a wire has to run from the switched power terminal to the starter button to the yellow wire for the starter. You don't have to disconnect either wire from the ignition switch, and if you DO disconnect the black wire from the switch, you'll get nothing, as you're now trying to run 100% of the switched power through the starter button, so you'll obviously not get anything if the button isn't pressed.

Connecting a momentary pushbutton IN PARALLEL across the black wire/yellow wire junction means you'll be able to use either the ignition switch OR the button to turn the starter. If you ONLY want the button to do the job, then disconnect the yellow wire from the ignition switch, and only have it connected to the starter button. If you want the starter button to operate even if the ignition is OFF, connect to the red wire instead of the black wire.

The red/switch/black sequence must remain in place undisturbed if the car is to work at all.

I agree with James. Wiring diagram shows the battery supply to 30 as a big red. Biggest wire going in - same size as the yellow.

Speaking of size. The solenoid is pretty heavy draw. With moving the power to the switched sources you are going to be adding to the draw across the contacts of that part of the switch. Normally the starter is going through dedicated contacts. I have no idea whether the ignition switch will be happy with that extra load. I'm real conservative so I would want to combine this project with putting a relay across the starter. There was a good thread back a few weeks ago.

The solenoid current is going through the ignition switch contacts in the stock setup, too. No difference there. Indeed, you're stressing the switch slightly less because you're running the solenoid current through a separate switch, but no more current is going through the ignition contacts than go through them if you use the stock starter switch.

If you wire the starter button to the big red battery wire instead of the switched power line, then you're bypassing the ignition switch entirely, stressing it even less, and running 100% of the solenoid current through the starter button only. IMHO, the relay at the solenoid is complete overkill. The 5A or so the solenoid draws is well within the range of most switches, you just don't want to use a milliamp rated microswitch.

James, thank you for your help. My confusion was with the word connect. I was connecting the black wire to the push button, instead of splicing a wire from it to the starter button. With a few bullet connectors, a splice connector, and some electrical tape, she starts!

Glad to help. A diagram would've helped, but I was too lazy to make one...

QUOTE (lapuwali @ Nov 27 2005, 02:47 PM)

The solenoid current is going through the ignition switch contacts in the stock setup, too. No difference there. Indeed, you're stressing the switch slightly less because you're running the solenoid current through a separate switch, but no more current is going through the ignition contacts than go through them if you use the stock starter switch.

gotta disagree James. Lets say the the solenoid draws 4 amps - no idea if that is even close but just for a number. In the stock setup that 4 amps comes from 30 and goes through a devoted set of contacts and out 50.

Granted in the new setup those contacts are no longer being used.

So he is now picking up power from 15 or somewhere downstream of that. Where does that current come from? From the same 30 along the internal buss, through the switched 12v contacts and out 15. From there through the new switch and on to the solenoid. The problem is that you have now added that 4 amps to whatever else normally goes through the switched power contacts that switch from 30 to 15. Further, if he doesn't pick it up at 15 of the ignition switch, and instead uses the distribution point over at s9 he is going through a '25' wire instead of a '40'. Again a worrysome plan for a conservative guy. Do you see what I'm driving at?

that james guy is alright.

Sorry to bring up a very, very old thread guys. I was reading some of the expert advice Lapuwali was giving regarding wiring a starter button, and even with his calm, cool, collected approach, I am confused. (Side note - he sounded like one heckuva guy, wish I could have met both he and Howard).

Could anyone expand upon what they were talking about? I need an idiots guide to wiring a starter button, preferably with an ignition switch (i.e. keyless). I've got all my wires run for my master kill switch, which seems simple enough, but I'd like to have a an ignition switch and starter button to eliminate headaches when it comes to race day.

A bonus would be if the instructions could include wire colors!