Another dim headlight question

[iowegian]

I am confused.
'66 Beetle.
6 volt.
very original car---well maintained its entire life.
fuse block nice and shiny. all connections appear good.

for this test:
Headlights are removed/ unplugged from bulbs.
taillight fuses removed....so the only thing powered up is the dimmer relay and the blue indicator light.

I just took some readings with my multi-meter with engine not running:
battery:6.36 v
generator :6.36 v
big red wire @ fuse block:6.35 v
Turn on headlight switch----readings at fuse block:
Low beam:6.29v
High beam:6.18 v PLUS .2 v+/- at Low beam terminals.
In other words, it appears that some High beam voltage is being "bled" to the Low beam circuit.
Is this normal? Can the dimmer relay have an internal flaw?

[EVfun]

You are loosing 0.2 volts to a bad ground connection. Check all the connection points from the headlight bulb ground terminal to, and including, a good body ground connection.
_________________

[iowegian]

[glutamodo]

The High Low relay is toggle, you only get power to one side or the other. This image is of a 12V version, but the setup is the same. At the bottom right you can see the contacts, they only route power in on direction or the other.

_________________
Andy T.


IMAGE NOTE: It has been noted that Chrome based browsers may have issues in displaying my vast image library, which use non-secure links and are on an FTP server. Images should still be viewable if the link is clicked though.
I do not know how to fix this. All I can say is it all works fine for me with what I use, Firefox.

[iowegian]

[EVfun]

[iowegian]

[Zwitterkafer]

That is baffling indeed. Does it still happen if you remove the high beam indicator bulb?
_________________
"Criticism comes easier than Craftsmanship"
- Zeuxius, 400 BC

[iowegian]

Well, I opened up the relay and I find nothing wrong (but what do I know?).
It looks like new, but I squirted some contact cleaner at it anyway.
Now I'll put everything back together and see what happens.

[iowegian]

[Zwitterkafer]

As someone else already pointed out, the relay is a binary device and is unlikely to have any leakage currents, particularly in one direction only. Where are you connecting your voltmeter to ground?
_________________
"Criticism comes easier than Craftsmanship"
- Zeuxius, 400 BC

[iowegian]

[Zwitterkafer]

The back of the speedo can easily be a less than perfect ground. Using a perfect ground elsewhere should eliminate any potential interference from the high beam indicator and gauge lighting circuits.

If the multimeter gives small spurious readings, it could be a fault with the probes and (if applicable) the tightness of the plug-in sockets. Sometimes a small re-tensioning of contacts can do wonders. Or just try a better meter.

0.2 V was not much....hopefully the mystery goes away with a tweak to technique or multimeter.
_________________
"Criticism comes easier than Craftsmanship"
- Zeuxius, 400 BC

[iowegian]

So far so good.
Using the dedicated ground I get the following readings:
Headlight bulbs not plugged in.
Taillight fuses removed.
Ignition off.

Fused side of fuse block where power comes from light switch---6.31 volts (same as at battery)

High beam socket at fender bucket----6.26 volts

Low beam socket " " " -----6.28 volts
(both left and right the same within .01 volt)


"crossover" not measurable.

I get the same readings using Chassis ground as with the "dedicated ground".

Quite honestly I do not know what changed, but I'll find out when I go for a drive after dark. Thanks for your help guys.

[EVfun]

[iowegian]

UPDATE:
Went for a short drive tonight and the low beams are about the same as they were before, but the high beams are MUCH improved. Why??---I do not know for sure.
On another related subject-------maybe I'll rethink the H-4s that are in it now and go back to good old fashioned sealed beams---------or maybe LEDs?

[KTPhil]

[toxicavenger70]

[KTPhil]

[toxicavenger70]