TheSamba.com :: View topic - I desperately need some electrical help..

Thu Aug 28, 2008 6:49 pm

Ok I've been trying to figure out this mess and I'm not seeming to get anywhere. I don't really have any experience with wiring so I'm sort of lost.

I've got a '72 and the front running lights refuse to work. Also the rear right brake light and running won't work. But all the blinkers work. Also wipers don't work either.

The biggest problem is randomly everything will start working then just die again, but always the same lights and the wipers. I've replaced all the fuses and bulbs and still nothing. So I'm pretty confused on how to track the problem down.

Oh and the needle on the gas gauge flickers like crazy any time I rev the engine. What could be causing that?

Thanks for the help!

Thu Aug 28, 2008 6:55 pm

Sounds like ground wire problems... get a test light or VOM and check for + power to items and hook up a "test ground lead" to the frame of the bus or - battery and use it to see if bulb holder/housings and wiper motor frame are getting a good ground.

Thu Aug 28, 2008 6:59 pm

I checked all the obvious ground wires and they seem to be fine. I don't have a volt meter though. I suppose I'll have to pick one up. Is there any easy way of checking without one though?

Thu Aug 28, 2008 8:02 pm

If your indicaters are all working your ground should be ok. Did you disassemble the whole light assembly or just pop a new bulb in? Both the front running lights/indicators and the rear bulb assembly have the contact pins in a plastic assembly that snap into the metal bulb frame which is grounded.

need to get access to the plastic piece so it can be worked on
- for the front unscrew the rectangular metal plate
- for the rear reach around inside the engine bay and pull off the long grey rectangular plastic protector on the light assembly.

Fine emery cloth is you friend. Clean up all the contact pins along with the spade slip on contacts. When you snap the plastic fitting back in to its slots make sure both sides are firmly in their place and they dont pop out when you install the bulb You can have one side of the plastic unit slip out so the pins don't make contact with one of the two bulb contacts. Also make sure the pins are making contact with the bulb correctly.

Not sure about the wipers. Start by following all of the wires checking all of the connections. I find the easiest access to behind the dash it to pull the ventilation levers, reach under the dash to behind the speedometer and unscrew the speedo cable. Also there are 4 screw at each corner of the dash that need to come out. If all looks good you'll need a wiring diagram and a test light to proceed any further. There are only 4 components: Power, Switch, Motor, Ground. Start at one end or the other and isolate each compnent and check to see if it is functioning correctly

Thu Aug 28, 2008 8:34 pm

Hey Ben
Normally I'd say grounds but this seems all too interconnected somehow.
And since you seem confident your grounds are OK, I would start checking all the connections to all concerned (except the fuel sender/gauge circuit - I feel this may be a separate issue). Samba has a wiring diagram here under Technical (if you don't own a Bentley manual) follow all the connections and check them. I mean really check them - pull off connectors, check and push back on if OK. I've come across a few surprises this way and found corrosion, loose connectors, connectors hanging on by a thread of wire, etc. Cleaned - replaced - everything happy again. I know this isn't a simple way and it's time consuming but it does pay off one way or another.
And of course your battery, generator, regulator, coil connections. Make sure every thing is clean and tight.
As for your fuel gauge going crazy when you rev - there maybe a little box that the the wire from the fuel sender goes to before it connects to the gauge - if there is - this a voltage stabilizer and needs to be replaced.
I'm not sure if you would have one of these but my 72 Beetle does.
Hope this helps and may the force be with you!

Thu Aug 28, 2008 10:23 pm

Success! (On the lights at least)

I totally disassembled the tail light housing and cleaned all the connectors and that appears to have fixed the problem. My license plate light even works now. And that had never worked in the past.

So tomorrow I'll try to figure out the wipers. I went over all the connections on it and still nothing. I'm wondering if the motor has possibly died.

Thu Sep 18, 2008 3:15 pm

My fuel gauge doesn't work and I don't really know where to start in order to fix it.

Thu Sep 18, 2008 4:32 pm

Start at the back of the gauge, check that it gets 12 volts when the key is on and goes to full when you ground the brown wire.