TheSamba.com :: View topic - 6 VOLT 66 with glowing red light at night

Mon Jun 25, 2012 2:16 pm

Hey All,
Here's a head scratcher for ya. Did a budget resto on my 66 beetle. Engine was rebuilt and engine compartment just about all done. I bought a lightly used, near new, rebuilt Bosch 6 volt generator and regulator from another Samba member. All in great shape with new brushes and shiny shaft. All connections are cleaned and shiney. I drove the bug last nite for first time at nite. With the headlites not on my car, at idle, the red lite flickers which is normal. With the engine not running, and turning the key on, but not starting, the red and green lites burn bright. Running the engine normally revved without the headlights on, the red flickering lite goes out(normal). When you put the headlites on at idle the redlite is not flickering. When you get the car revved up at a normal speed the red lite starts to glow very faintly. When you hit the high beams it glows a little bit more, but in both cases it is faint and nowhere near the brightness of the redlight when you first turn the key on without starting the engine. I checked my battery with the following readings.
with engine not running...6.19v
running at idle...6.25
running at medium high rev...7.91
low beams with engine running at idle...5.97
high beams " " " " " ...5.95
low beams with eng. at medium high revs....6.73
high beams " " " " " " ...6.67
These all appear to be normal readings. Since the gen and voltage regulator are new to the engine I thought that maybe I should polarize the generator. I did the polarization procedure that is outlined in many of the previous posts and it spun the generator with the pulley off just fine. Put everything back together and took volt readings at my battery again and got the same readings again. My car runs just fine, my battery is a 6 volt Optima, and it has never gone dead or needed charged. This faint red lite glow with the headlites on is just a bit of a worry to me. I think I read in the Muir book that this is a common and normal thing that occurs in older VW busses. Anybody elses 6 volt bugs do the same thing?
Thanks!
John M. in Pa.

Mon Jun 25, 2012 2:43 pm

Have you cleaned your very basic connections?
Battery terminals
Starter terminals
Regulator terminals and mounting.
Ignition switch terminals
Fuse box and Speedometer light terminals.

You have a voltage drop somewhere, and can be either ground or power.

You are not alone... now get to shining up all your connections.

EverettB wrote: The light being dim at higher rpms is not really abnormal on an old VW, this just means there is a mismatch in the voltage between the light and your regulator output. Cleaning connections and making sure the regulator is putting out the proper voltage can fix this issue.

Hammarlund wrote: Usually, when the light is not on at idle or low rpms, but gets brighter as rpms increase, the charging system is doing ok, but there is a bad connection somewhere in the cirucuit of the light itself. This is especially likely to be the case if your battery has not been going dead.

To be sure, you can measure the voltage appearing across the battery with the engine running. If the voltage does not vary when you flick the lights on and off, everything is probably ok.

In that case, carefully cleaning and brightening all the connections might make the flickering go away.

Bruce Amacker wrote:
I agree cleaning of all connections would be a good start and don't forget the ground strap under the tranny. Having the voltage drop from 7.4 to 6.4 when the headlights are turned on is a sign that your generator is not putting out enough amperage. (I assume this voltage drop is at the same 2000 RPM? 6.4v at idle with the headlights on would be a correct voltage, since generators charge very little at an idle) This could be caused by corroded connections or a weak/failed component such as gen or regulator.

My buddy's '66 Beetle also glowed the light occasionally until he changed the complete wiring harness.

Do you know how to do a voltage drop test? It's quite easy using any cheap DVOM and a long test lead. This would confirm or rule out connection problems in your harness.

Good Luck!

Mon Jun 25, 2012 6:08 pm

tHANKS FOR all your replys. During my resto I thought I cleaned all the contacts of everything. I'm going to look at the redlight connections closly. Before the engine was rebuilt and had my old filthy generator/regulator, this event did not occur.....also my car has this strange extra selanoid that,s screwed to the top of the rt. rear inner fender above the starter. It looked pretty crappy and the push terminals are steel not copper. I will try the red light first.....Bruce, I do not know how to do a voltage drop test. Can you refer me to a post that explains how to do this? I have a simple voltmeter.

again, thanks for all the advice!

John M.

Mon Jun 25, 2012 6:43 pm

I quoted all of those from posts I searched about the same issue... so getting Bruce to respond might not happen.
To perform a voltage drop. You test a circuit with it loaded.
Ill try and simplify how to perform the test...
You dont look for battery voltage you are looking for loss of voltage.
You will need a good volt meter with good leads. A digital meter will give you beter and very accurate readings.
Start by cleaning all the battery connections, both ends to eliminate those.
Ill make it very simple.
One small circuit example.

Test the voltage drop of the speedometer warning lights supply circuit.
Turn your key on, place one end of your lead at the igntion switch battery supply, and the other at the lower spade at the speedometer. You should have very low votage loss. You are now testing, the igniton switch terminals, contacts, the wiring to the fuse block and the wire to the speedometer warning light. Voltage drops will vary in readings, but you really seldom want to see any voltage loss over 1 volt. With a 6 volt system you'd better not see much over .5 volt. In a circuit that small you shouldnt see much at all.

You can test every circut on a car that way. You leave everything connected, and you MUST have the circuit loaded. That means what ever circuit you are testing must be turned on and working.

This testing will drive you absolutely nuts if you're unsure as to what to expect the results to be. ..
Some times most times its easiest to just clean, but a voltage drop test WILL find problems.

Tue Jun 26, 2012 6:27 am

Thanks very much Volkswagnut and others! I think that since this occurs only when the headlights are on I should go back to my headlight connections and super clean them again and the ground connections...and the red light connections also. Thanks on the "how to" advise on the individual circuit testing. You guys are great!

John M.

Tue Jun 26, 2012 7:17 am

Its probably not the headlight circuits, but the main, and fuse / ignition feed circuits.
Clean the terminals.. Make them bright and shiny. Apply Die-Electric grease to the terminals to aid in oxidation prevention.

By the way.. the strange looking solenoid mounted near the fender, is most likely an old Ford Starter Solenoid.. used sometimes on cars with connection issues... as a "Hard Start Relay"

So what does that tell ya. :wink:

It usually looks like this... but can be mounted anywhere... in close proximity of the starter...

Tue Jun 26, 2012 1:03 pm

Ah, yes - the old "extra universal solenoid switch mounted in line with a 6 Volt VW starter" trick. Works every time. The next step is mounting a push button starter switch in the kick panel under the rear seat. That will also help combat voltage loss on 6 Volt VW's.

As far as the red light goes, you may want to try pushing the generator brushes in a little bit with a screwdriver on top of the hold down spring while the generator is spinning (running). Not too much pressure, just enough to ensure the brushes are solidly seated and making full contact on the commutator. Maybe the new generator's brushes aren't fully burnished yet.

Tue Jun 26, 2012 5:46 pm

Quote: with engine not running...6.19v
running at idle...6.25
running at medium high rev...7.91
low beams with engine running at idle...5.97
high beams " " " " " ...5.95
low beams with eng. at medium high revs....6.73
high beams " " " " " " ...6.67
These all appear to be normal readings...

These are not normal readings, and they indicate that your voltage regulator is not working properly, even if it is new.

Volkswagen specified a range of 6.4-7.3 volts for the regulated voltage under load, which is what you read when you put your voltmeter directly across the battery terminals.

This does not mean that it is ok for the voltage to vary widely as long as it stays in this range. It means that any constant voltage in this range is acceptable. The voltage should very only slightly as you rev the engine, and flick the lights on and off. In fact, this is how many of us test the regulator.

At this point, it would be wise to abandon all your assumptions and go to Rob and Dave's Aircooled web page. Find the page titled, "Fault-finding the VW Charging System." Run all the tests there, carefully following the procedure and taking notes, and you should find your problem.

On a related note, the hard-start relay is often (usually?) installed because the owner is unable or unwilling to find and fix bad connections in the car's electrical system. These cars did not need them when they were new and the electrical systems were in good shape, and they usually don't need them now if the owner takes the time and effort to make sure all the connections are solid.

Find and fix all the faults in your car's electrical system, and you can pull that relay, and you may fix your charging problem, as well. In particular, make sure the ground straps (there are two) are properly installed and in good condition.