TheSamba.com :: View topic - Brown Wires(Ground) On the Back of the Speedometer

Sun Oct 05, 2025 6:39 am

Hello, I have a 1974 Super Beetle that has some loose (Ground) Brown Wires at the back of the Speedometer at time of pulling the Speedometer out to replace a "High Beam Indicator" Bulb.

Point is that I have one "Brown Wire" that is loose at the back of the Speedometer now.

But...

Thing is now I have "Hyper-Flashing" of the Turn-Signals.

I did not touch anything else pertaining to the wiring harness.

So, question is this, where do all the (Ground) Brown Wires tie into on a 74 Super Beetle?

I am having a time with the Orange Super Beetle/Ghia Book, need new glasses, lol..

But yes, working on the car after it sat for a bit.

All knowledge is appreciated.

RB

Sun Oct 05, 2025 7:32 am

RailBoy wrote: Hello, I have a 1974 Super Beetle that has some loose (Ground) Brown Wires at the back of the Speedometer

Point is that I have one "Brown Wire" that is loose at the back of the Speedometer now.

Tighten those !!!!!

RailBoy wrote:
So, question is this, where do all the (Ground) Brown Wires tie into on a 74 Super Beetle?

Ground wires should all have good clean tight contact with metal of the pan. metal of the body, or metal of such accessory/part. If connections are right, should not matter much.

Sun Oct 05, 2025 7:43 am

Quote: now I have "Hyper-Flashing" of the Turn-Signals

Coincidence, the turn signal circuit doesn't need to have a grounded speedometer to work. You should ground the brown wire, the dash lights in the speedometer need a ground to work properly.

Sun Oct 05, 2025 8:32 am

I have some things coming on so there is a "good" ground out of the batch that are attached.

Thing is my "Hyper Flashing" of the relay, it goes so fast the lights on the fenders do not illuminate.

I am diving into it now, and looking for scrapes on the Speedometer's ground housing to see if this one that is not hooked up does get hooked up.

Thing is, it has old black electrical tape on it. So, not sure if it simply popped off when I pulled the speedometer out?

RB

Sun Oct 05, 2025 12:50 pm

Quote: my "Hyper Flashing" of the relay, it goes so fast the lights on the fenders do not illuminate

"Hyper Flashing" is an indication of a burnt out bulb. 8)

Sun Oct 05, 2025 1:05 pm

RailBoy wrote: Thing is my "Hyper Flashing" of the relay, it goes so fast the lights on the fenders do not illuminate.

Thing is, it has old black electrical tape on it. So, not sure if it simply popped off when I pulled the speedometer out?

What's the turn signal indicator in the speedo doing? Is it connected to the flasher? Are you using LEDs for the turn signals? If you are using an aftermarket flasher, it may have a separate ground wire that's not making a good connection. Photos would helpful ... it gives us the opportunity to see if we spot something that is amiss.

Sun Oct 05, 2025 1:47 pm

Hello, well I just got done messing with it and made no headway.

It was all fine until I pulled the speedometer out of the speedometer's Speedo Bucket.

There are no LED's anywhere on my car, also, stock Flasher.

I did two test while I was out just to double check with all the brown wires hooked up.

With the key on, so I had power, there was "Hyper Flashing".

Then, I just turn the turn signal on left side then right, and the flasher worked in a traditional since, just normal blinking.

Then, I had it back to "No" blinkers, and back to "Hyper Flashing".

So, "Engaged" Hazzards, and the Flasher worked as stock flashing, and all four corners at the fenders worked fine.

Then back to all off, and went back into "Hyper Flashing" mode. So fast and I am not sure, but, no fender lights, just can see the Signal Indicator "Hyper Flashing".

So, shut the key off, all went off, and disconnected the battery.

Also, everything is stock, but been reading that the Emergency Hazzard switch can act up and cause this, which I guess goes away when you engage the Emergency Hazzards.

Know what is screwy, is that when you pull the "Turn Signal Indicator Bulb" out of the Speedometer, it looses a ground. But in doing so, the Hyper Flashing goes away.

Now what does that mean?

And on the up and up, I need a new perscription for eye glasses, which is not helping when it comes to reading the book's electrical diagram.

RB

Mon Oct 06, 2025 12:27 pm

RailBoy wrote: With the key on, so I had power, there was "Hyper Flashing".
(...)
Then back to all off, and went back into "Hyper Flashing" mode. So fast and I am not sure, but, no fender lights, just can see the Signal Indicator "Hyper Flashing".
Sounds like it is only "Hyper Flashing" when the turn indicator should be OFF, turn signal lever is centered and the E-Flasher switch is OFF. Is this correct?

Question, when the turn signal lever is in the left or right turn position and the corner lights are flashing normally... Is the turn indicator lamp in the speedometer flashing at the SAME TIME as the corner lamps, or does it flash OPPOSITE from the corner lamps? If wired correctly the speedometer indicator lamp will flash ON when the corner lamps flash OFF (OPPOSITE).

Rail boy wrote: Know what is screwy, is that when you pull the "Turn Signal Indicator Bulb" out of the Speedometer, it looses a ground. But in doing so, the Hyper Flashing goes away.
So with the turn indicator lamp removed from the speedometer the corner lamps all work normally for both turn signals and the 4-way E-Flasher? This suggests the problem is likely one of the following...
1) You have the speedometer wired incorrectly. You hinted above that removing the indicator lamp from the speedometer will cause it to "loose a ground". Are you thinking the turn indicator bulb holder is grounded thru the opening in the speedometer? Actually, the turn indicator lamp turns ON when the wire coming off the removable bulb holder is grounded. The three indicator lamps at the bottom of the speedometer share a common 12v+ power coming from the bottom most terminal. The black (or green) wire that connects here comes from the fuel gauge (earlier model years ran a wire directly from the fuse box). If you disconnect this bottom most wire and test it for voltage while the ignition switch is ON you will find 12v+ coming from this wire. This is the power source for the bottom three bulbs. Each of the wires from the three bottom bulb holders runs to a "switched ground" which turns the indicator lamp ON. This "reverse polarity" only applies to the bottom three warning/indicator lamps. The other illumination bulbs in the speedometer do use the case of the speedometer as their ground.
A common mistake is to look at these three bulbs at the bottom and see the common connection point and assume it should have a ground wire connected to the bottom terminal. This is incorrect. Check the wiring at the bottom terminal of the speedometer. If your speedometer is wired incorrectly the GEN and OIL lamps likely do not turn ON when you first turn the key to the ON/RUN position. These also work off a switched ground wire.

2) Your flasher relay is either the wrong type or is starting to fail. With the turn indicator lamp disconnected you can use pretty much ANY 12v flasher relay. But once you connect the turn indicator lamp to the #49a terminal of the flasher relay the relay will "see" 12v+ coming into its pulsing 12v+ output terminal (49a). Some generic flasher relays will not work wired this way.
If you need a new flasher relay, go to your FLAPS and find a 3-terminal EP35 flasher relay which has the proper terminal numbers: 31, 49(+) and 49a. This relay was designed to work with the VW Beetle wiring. Does your relay have the correct terminal numbers (indication it was meant to be used with a VW)? If your flasher relay has the USA-common X, L and P terminal numbers it may not "play nice" when the turn indicator lamp is connected to the L terminal.

Just so you know... the VW speedometer turn indicator lamp operates on the following principles:
- Incandescent bulbs turn ON when enough current is flowing thru the filament to heat it up enough to cause it to glow. Lacking enough current flow the bulb will appear to OFF. The precense of voltage at a bulb does not alone confirm a bulb will turn ON if current is not flowing thru the bulb filament.
- Current flows from higher voltage to lower voltage. The greater the difference in voltage the greater the potential to do work. The smaller the voltage difference the less potential; down to zero potentail when the voltage difference is zero.
- Applying 12v+ to both ends of the bulb filament results in zero voltage difference across the bulb terminals and STOPS the flow of current thru the bulb; turning the lamp OFF.
While most think of flashing a bulb by constantly grounding one side and alternating its power source from 12v-0v-12v-0v. It is also possible to flash a bulb by providing a constant 12v+ source on one side and alternating the ground path from ground-12v-ground-12v. When grounded the bulb will turn ON. When 12v+ is applied opposite the constant 12v+ coming into the other side of the bulb there is 0v difference across the bulb so no current flows, causing the bulb to turn OFF. The turn indicator lamp works off this later principle. When the flasher relay 49a powers the corner lamps it STOPS the current flow thru the turn indicator lamp in the speedometer so it turns OFF. This is why the turn inidcator lamp flashes opposite the corner lamps.
- A small wattage (2W) bulb grounded thru two large watt (21W x2) bulbs will allow the 2W bulb to turn ON while the 21W bulbs will appear to be OFF even though a small current is flowing thru them. This is how the turn signals work to light up the speedometer indicator lamp. When the turn signal lever is in the L or R turn position a path to the corner lamps opens. When the flasher pulses OFF the turn indicator lamp "sees" a path to ground thru the corner lamps. Current flows thru the speedometer indicator lamp turning it ON, but the watts are limited to just the 2W bulb rating. This 2W is much too little to warm up the two 21W corner bulbs so they remain OFF even though some current is flowing thru them to ground the indicator bulb.
- (E-Flasher reverse flow) With the ignition circuit turned OFF and the E-Flasher turned ON, the turn indicator lamp in the speedometer is powered in reverse by the flasher relay output (49a). The turn indicator lamp in the speedometer becomes a 5th corner lamp. The current from the flasher relay 49a passes thru the indicator lamp and flows backwards thru the ignition circuit. In the same way the indicator lamp grounds thru the corner lamps with the turn signals, it finds a path to ground backwards thru all the other ignition switch powered devices (ignition coil, choke coil, idle cutoff solenoid, GEN lamp, OIL lamp, etc). The 2W coming thru the bulb is too little current to power anything but the current does find a path to ground so the indicator lamp now flashes in sync with the corner lamps as they are all powered from the same 49a terminal of the flasher relay.
Interestingly, if you turn the ignition switch ON while the E-Flasher is ON you will see the speedometer indicator lamp switch from in sync flashing (E-Flasher only) to opposite flashing (E-Flasher + ignition switch is ON).

Mon Oct 06, 2025 1:26 pm

RailBoy wrote: I have some things coming on so there is a "good" ground out of the batch that are attached.

Not necessarily true.

If you lack a proper ground, current will seek an alternate path, such as through a second bulb filament or even a relay winding.

Mon Oct 06, 2025 4:10 pm

KTPhil wrote: RailBoy wrote: I have some things coming on so there is a "good" ground out of the batch that are attached.

Not necessarily true.

If you lack a proper ground, current will seek an alternate path, such as through a second bulb filament or even a relay winding. So true. Not only does it seek the path or least resistance it also seeks any path.

Tue Oct 07, 2025 7:02 am

Runamoc, I do have a good ground on my speedo currently for the Speedometer's illimunation lights come on, pus the oil and gen red lights come on with out starting the car.

Ashman40, can you explain more on the green wire that runs into the fuel gauge viberator that becomes black(+) tied into it? Thing then there for I doubled checked I would create a short, do to the cluster is grounded to the speedometer body.

My Black Wire that comes from the fuel gauge is unattached currently.

Thing is this, I did not know I was doing it at the time, but, in pulling the speedometer out, I did "Maybe" pull two wires off.

They are the loose Brown that has tape on it, so not to conduct any type of issue for it did have really old black electrical tape on it, and then I found the Black Wire unattached to anything. Which I could have knocked off?

Point, is that I currently do not have any wires other than the wires running to the Gen Light Indicator Bulb, Turn Signal Indicator Bulb, and the Oil Pressure Indicator Bulb.

Thing is there are I think two tabs that look like grounding Spade Tabs that have nothing going to them. And in your post, are you speaking of the Two Open Spade tabs in this cluster?

See, I read in a Ghia, that there is a isolation piece of thin rubber from the housing of the Speedometer housing, but, my Gen, and Oil Pressure lights work fine, and as mentioned, when the Turn Signal Indicator Bulb is in, Hyper-Flashig occurs. So, the cluster that has these 3 Bulbs is grounded, but, I thought the Speedometer Housing is Grounded(-), thus, would short with the Black/Green(+) (Fuel Gauge) Wire?

Is this cluster of 3 bulbs(Gen, Oil, Turn Signal) the cluster you said that the back wire ties too?

Yea, a bit screwy here on this post, but so far, just found a loose Brown, which is not grounding to anything; Key-Off, Turn Signals Engaged, Flasher Engaged or anything, and this is with the key on, but battery disconnected.

And I was using a "Continuity Tester".

Just some insite on something I know I saw the isolation pad of thin rubber between the 3 hight cluster and Speedometer Housing of the Ghia, but I have a 1974 Super and on the housing of the speedometer, there is a separation pad between the three bulb cluster and speedometer housing, but, the rivets that connect the cluster of three bulbs(Gen, Oil, Turn), ground the cluster of the three bulbs out, so is there a difference in notes here for you as well as what you posted to be connected, (Black/+)? Confusing me some here.

But yes, I have been looking at the VW Super Beetle Book (Orange Book, by Volkswagon) and its a bit screwy it seams to me.

RB

Tue Oct 07, 2025 8:23 am

Quote: the oil and gen red lights come on with out starting the car.

The idiot lights and turn signal arrow are mounted in a plastic piece that's at the bottom of the speedometer housing. It is electrical isolated from the speedometer housing because it's made out of plastic. Wire #15 power (power with key switch on) is connected to a male tab at the bottom of this plastic piece and is common to all 3 bulbs. The male tabs on these bulbs go to other 'things' that supply a ground reference to illuminate them. They would still work just hanging by the wires with no speedometer.

Tue Oct 07, 2025 8:31 am

Runamoc,

I turn on the key with the brown wire that is not connected to anything and ran continuity test between it with turn signals, hazzards on, but to cover it, no battery power.

So, either the Flasher Relay is not engaged creating a gap in grounding, or it is totally not hooked up on the other end.

I did two test with the continuity tester, extra brown with key on and signals/hazzards on with ground at the battery and positive.

Why I say that this particular ground is not tied into anything, if the flasher relay, no continuity there for no power to activate it. Or this, the hazard switch took a dump on me, for I am thinking of two items that I ordered could be causing this, one of them I am wondering, the Hazzard switch of Flasher Relay?

#15 wire, I will check into it with the book, and see what it comes from into the speedo housing.

RB

Tue Oct 07, 2025 1:37 pm

Ok here it goes, I forgot to undo the positive terminal from the battery thus when I pulled the speedometer, I not only pulled the #15 Black wire from the cluster(6 O'clock) of two spades that power the Gen/Indictor Signals/Oil light, I also touched the housing back feeding the Flasher Relay, for then the Black wire(#15) came undone from the 3 light bulb indicator Speedo's Cluster, that is operated from the Speedo's housing that is negatively grounded for Illumination Lights, Fuel Gauge, and High Beam Indicator, I fried the Flasher Relay.

See, then in a nut shell. Thus messing up the Turn Signal Indicators and back feeding them w/Gen Power, like when you go to start up the car, power is drawn from the battery thus illumination of Red Generator till you get the RPM's up. Here the Key is on the "On/Run" position.

Does this make since?

But in all, from the statements from everyone we are all correct, I just have I am thinking a wasted Flasher Relay now.

But I do have an Emergency Hazzard Switch on the way as well, plus some bulbs and fuses.

Let me now if you catch my drift from this current post?

RB

Tue Oct 07, 2025 1:49 pm

RailBoy wrote: Ashman40, can you explain more on the green wire that runs into the fuel gauge viberator that becomes black(+) tied into it? Thing then there for I doubled checked I would create a short, do to the cluster is grounded to the speedometer body.

My Black Wire that comes from the fuel gauge is unattached currently.

Thing is this, I did not know I was doing it at the time, but, in pulling the speedometer out, I did "Maybe" pull two wires off.

They are the loose Brown that has tape on it, so not to conduct any type of issue for it did have really old black electrical tape on it, and then I found the Black Wire unattached to anything. Which I could have knocked off?

Point, is that I currently do not have any wires other than the wires running to the Gen Light Indicator Bulb, Turn Signal Indicator Bulb, and the Oil Pressure Indicator Bulb.

Thing is there are I think two tabs that look like grounding Spade Tabs that have nothing going to them. And in your post, are you speaking of the Two Open Spade tabs in this cluster?

See, I read in a Ghia, that there is a isolation piece of thin rubber from the housing of the Speedometer housing, but, my Gen, and Oil Pressure lights work fine, and as mentioned, when the Turn Signal Indicator Bulb is in, Hyper-Flashig occurs. So, the cluster that has these 3 Bulbs is grounded, but, I thought the Speedometer Housing is Grounded(-), thus, would short with the Black/Green(+) (Fuel Gauge) Wire?

Is this cluster of 3 bulbs(Gen, Oil, Turn Signal) the cluster you said that the back wire ties too?
This pic illustrates the point... notice the white bit of plastic that insulates the three bulb openings at the bottom of the speedometer from the metal case of the speedometer.

You can see the speedometer illumination bulb openings at the left and right are part of the case so ARE grounded by the case of the speedometer. This is why when the headlight switch applies power to the wire running to these illumination bulbs they light up. But the three indicator bulbs at the bottom ARE insulated from the case so are NOT being grounded. The two male spades closest to you as pictured are the bottom most spades (some years only had a single male spade). The green wire on the right spade runs up to the fuel gauge vibration which is powered from the fuse box. While you cannot see it clearly, the two male spades at the bottom of the speedometer are part of the same shiny metal that the bottom three bulb holders slide into. So while the illumination lamps of the speedometer are grounded by the case, these three bulbs are insulated from the case so they can be powered by the green (or black) wire coming from the fuel gauge so all three indicator lamps share a common 12v+ power source (insulated from the case so there are no shorts). If you get a phone camera in there on your car you can probably take a pic to assure yourself that the bottom three bulb holder openings are NOT grounded to the case.

Reconnect the black(?) wire coming from the fuel gauge vibrator to one of these bottom terminals. Reconnect the turn indicator lamp between this 12v+ source and the 49a terminal of the flasher relay and confirm your turn signals and E-Flashers work as expected.

Also make sure the GEN and OIL lamps turn ON when you first turn the key to the ON/RUN position.

I don't know HOW you had GEN and OIL lamps without the black wire connected to the bottom of the speedometer??? All I can tell you is how the stock wiring was meant to be.

Tue Oct 07, 2025 2:07 pm

Hello and Thank You Ashman40.

Thank you for the image.

I plan to put in the new flasher relay once it shows up to see if that clears up the hyper flashing?

Also, thing is, somehow do to me of course not pulling the battery cable, I most likely fryed it.

But yea, why or how does the turn signal indicator illuminate with no 6 O'Clock wires attached like your green, a couple thing, ground out oil pressure switch for that is stock, or gen indicator light continuity. That I would think is battery supply like when right before the key starts the car illuminates, this creating the circuit for the back feed to occur, thus hyper flashing or the now bad flasher relay, or failing one.

RB

Tue Oct 07, 2025 3:02 pm

Quote: wasted Flasher Relay now.

did you replace it with one like this?

Tue Oct 07, 2025 3:09 pm

I have ordered one yesterday, to prep.

RB

Tue Oct 07, 2025 3:26 pm

RailBoy wrote: I forgot to undo the positive terminal from the battery thus when I pulled the speedometer
RailBoy - if you want to become RailMan someday, you'll remember this and ALWAYS pull a battery cable before doing any electrical stuff more than troubleshooting.

But I recommend to pull the NEGATIVE cable, like most experts do.

Tue Oct 07, 2025 3:31 pm

Cusser, you got me there, that is for sure.

It has been a while since I messed with the Super.

I installed all new fuel lines, Fuel Filter,
and putting on a new horn.

Everything is coming along, and I hope once I get the
new Flasher Relay in, and Black(+) wire hooked up at
6 O'Clock, on the spade my turn signals come back.

Also, I am hoping with the order of bulbs, it is a bulb that
went with the High Beam Indicator on the Speedo.

Thanks for the chatting on the car and appreciate the knowledge.

RB