Weird electrical short in 74 standard beetle..HELP!

On the first problem you're clearly in the right area. I'd disconnect the switch and see if the resistance goes infinite, for starters. Shorts can be hard to find and sometimes you need to isolate parts of the circuit to find it.

That second problem with the headlight switch out I've seen on other cars and that's usually ground related (or on some newer cars the load sensor, which I don't think a 74 beetle has). Most likely your headlight or alternator has lost its normal way to ground and is using another path. Since that other path may not be able to handle the increase in current, the voltage drop across that connection increased, causing problems in other areas. Try bridging your grounds with a booster cable and start with the connection from the battery negative to the engine. Only use the negative side and walk it between points that should be grounded to see if the problem wants to go away. After you found where it wants to go away, you look into what ground point has gone bad in that viscinity.

Just to clarify more: make sure your battery voltage does not change when the VDO changes voltage. If it changes, your alternator/generator is clearly loaded beyond what it can handle or is bad. If it does not change, your voltmeter gauge may be hooked up to the end of a wire that heavily loaded - it could actually be related to having a bad ground, depending where you hook that Vgauge up to.

Remco,

I think I follow you. Could you suggest a proper connection for the VDO gauge? That could be the problem, for i see noticible drop when any light is turned on whether flasher etc and could be the source of my issue. I will disconnect it and retest........if problem is gone, i have found source.

On the first problem, I think i found the issue. I suspected bad hazard switch, and it was fine. But to get to the switch i had to remove the radio. Guess what? short went away. I have the yellow "memory" wire going to fuse 8. However when the radio was still hooked up and the fuse 8 was pulled, it did not work.

I know when i hooked the radio up, i chose a "key on" wire for the power source.........and it did NOT work when the key was off...........so thus i am confused as to WTF is going on there. These tests definately show the radio is pulling a full draw when the car is off and it is connected.

Your thoughts?

Remco wrote:

So this is an aftermarket, new radio then. Are you sure that the yellow wire is just for memory? It shouldn't draw very much at all. Not positive on this, but seem to remember yellow is usually the dimmer wire or the power antenna wire. If you have the manual, make sure. If yellow truly is memory, perhaps unhook all wires except it and ground to see if the current is still high. If so, that radio may have a problem.

On the voltmeter, I'd hook a small fuse in series with the hot close to the point where you intend to measure - radio shack sells those in-wire fuse holders which will do a good job. This way, should the wire to the voltmeter ever be pinched, it will not cause a dangerous condition. It also buys you the advantage that you can safely hook that voltmeter up anywhere. Ideally you'll want to put it as electrically close to the battery as possible. The most practical may be the common non switched hot connection on your fusebox (now you see why I suggested that the voltmeter has a fuse in the line),

Now that I am sitting behind my first cup of coffee of the day, let me change one thing:

Hook that voltmeter across a /switched/ connection electrically as close to the fuse box/battery as you can. Find the connection that has the least amount of current going through it so the voltage drop from the fusebox to the battery is the lowest (and your voltage reading the most accurate).

My previous suggestion of hooking it to an /unswitched/ connection would obviously not be a great idea as the battery may slowly drain.