Which ignition live? (beetle)

[andy198712]

Hello.

Had my 1972 standard beetle running my MS for a while now but use a push button start.

i went to change back to the key start and the car would just spin over but not catch, this was because i found the wire i take my ignition live from at the fuse box, to power the relay for MS cuts out when i turn the key that extra bit to start.... Thus my starter button works fine but the key does not...

So which fuse have you guys and girls taken your feed from that has power while cranking? (to save me cranking it a lot and checking which is hard one manned! )

Cheers

Andy

[Clonebug]

The wiring harness for yours is much more complicated than the 67 diagram I used on my buggy.....

From what I can tell it is pretty well a direct shot from the main power on the starter.

http://www.superbeetlesonly.com/forum/pages/et/72.jpg

[Dale M.]

The key "on" position should be HOT all the time when key is on and also when cranking starter.... Wire to coil (for example) should come off any fuse that has power (12 volts) when starter motor is in operation this should/could also be used for master power relay for MS......

In diagram below it equates to top fuse position on left side.. (#1 or #12 not sure which way it counts)....

http://www.superbeetlesonly.com/forum/pages/et/72.jpg

Dale

[Marc]

The key "on" position should be HOT all the time when key is on and also when cranking starter....

Yes. I suspect you're trying to use the "X" terminal, something that debuted in 1971 to allow the ignition switch to control power to the headlamp portion of the lighting switch - that one goes "off" when cranking to allow more current to the solenoid if the the headlamp switch is in the on position when cranking.

[andy198712]

Yeah i think i probably am using the headlight fuse i think?

yeah they got loads of stuff in them after 70 ish!! mine being a 1200 doesn't have half that stuff but i get the idea

Yeah looks like the top two fuses will work, i'll take a look at mine and see which side that is and give it a go!

Thanks guys

[Dale M.]

It goes on UNFUSED side..... OF whatever fuse position you use...

Dale

[andy198712]

Ok, wouldn't have known that, guess it goes via my fuse board for the ms anyways.

Thanks again, will let you know how I get on tomorrow

[Dale M.]

I was referring to stock coil wire on unfused side..... But it really does not matter if you are only operating a relay, it can be fused...

Dale

[andy198712]

Got it

[andy198712]

Moved it to the second one in, popped a the clip from a test light on the terminal and had the light bit in the cabin so i could iff if it stayed on while turning the key, works fine thanks guys!

next step is to run a thick cable to the front of the car and make a separate fuse box up there fed via a relay to be ignition live so i can take some of the strain and birds nest off the stock fuse box and just have the AUX box for the things like the ECU, eberspacher, water jets, rpm gauge yada yada....

[Clonebug]

Use the original main power and split that under the hood.
I installed a second fuse box that is always powered for the items that need that. The original fuse box is still only powered by ignition and takes care of those items. I need to add a relay to that box but I might get to that this winter.

Here is a pic of the start of the mess.....sorry about the wires spread everywhere.........

[Piledriver]

Note that on a late factory setup a bad ignition switch can cause similar symptoms, mine had an intermittent dead spot on the ign output between run and start.

[andy198712]

I need to post you a picture of my rats nest!!

Yeah I guess I could just take off from the factory love like you say, saves running a cable and it's pretty thick gauge so should be able to do the heater, gauges, head unit I reckon

I'll keep an eye on my switch, been ok for the last 5 years but I know they can get dodgy!!

[Marc]

...I'll keep an eye on my switch, been ok for the last 5 years but I know they can get dodgy!!

Don't forget about that "X" terminal (should be black w/yellow stripe) which can be used for loads which don't require power when cranking - takes some of the load off of the main ignition Term 15.

One nice thing about the modular ignition switches which debuted in `72 is that when one does start to go bad, you can drive with a new one hanging out from under the column until you get around to pulling the wheel to install it properly...I carry a spare in my glovebox.

[Dale M.]

I need to post you a picture of my rats nest!!

Yeah I guess I could just take off from the factory love like you say, saves running a cable and it's pretty thick gauge so should be able to do the heater, gauges, head unit I reckon :)

I'll keep an eye on my switch, been ok for the last 5 years but I know they can get dodgy!!

Be aware of the wire gauge of original "Hot" lead from battery to front (ign - fuse panel) if you load it up to much you will start getting a voltage drop at some point when the amperage load exceeded wire gauge capabilities and also possibly over loading conductor and melting insulation.... Just FYI...

Dale