Generator light always on

smtichy

smtichy

Senior Member
I'm sure you all have similar luck, you let someone else touch your car and then some weird thing shows up. Today I had my car in for a technical control, and when the technician finished I noticed this ....

The GEN light on my '55 (now) stays on when the car is turned off, and even when the key is taken out of the ignition :eek:. When the car is running it is off as normal.

Before I start tearing into it, has anyone come across this, and any tips on where to start fixing it. :confused:

By the way, what a lousy experience, the guy goes on to tell me the car looks great on the outside, but underneath it is very oily, has a little rust on the frame, and has been poorly renovated. What a clown, this car has never been restored, and it leaks about a teaspoon of oil a month ... irritating to hear those comments instead of a compliment and encouragement to preserve a piece of history. :mad:
 
NEVER let anyone else do work on your car. They don't care about anything. Idiots will spill oil down the generator during an oil change.
 
Steve, what exactly did the "idiot" DO during the Technical Control (Is that some sort of inspection?).

With the key in the off position, there should not be any power to the indicator light. It connects to the Accessory Pole of the Ignition Switch ( as does the oil light).

Looking at my wiring diagram it appears that the only power it can get with the switch off is IF it is back feeding through the voltage regulator.

Without knowing what he touched it is difficult to say. Best to get the test light and/or volt/ohm meter out and test the circuit and voltage regulator.
 

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darrell - yes my '55 is still a 6 volt.

Y-Blockhead said:
what exactly did the "idiot" DO during the Technical Control (Is that some sort of inspection?).
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Yes it is a sort of inspection, where they verify the car is roadworthy, this is common in most European countries. I've just brought my '55 over to Czech Republic, and this was it's initial test for registration.

The "idiot" just drove the car from test station to station (testing brakes, shocks, lights, etc.). Starting and shutting the car off at each, and racing the engine a bit between each as he had trouble figuring out the 3-on-the-tree.

Based on your diagram, and the following comments, I'll start with the regulator. Thanks!
p.s. - if the regulator is the source, can I repair it? or does it need to be replaced?
 
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Y-Blockhead said:
^^ This is true if they're familiar with '55 Fords in The Czech Republic, haha
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You're right, that and the 6 volt will have them baffled.

You all should have heard the geezer inspecting the car, he was jabbering some nonsense about how in those days neither the Americans nor the Soviets knew how to build proper automotive headlights, and so on.

I bit my lip and kept quite ... :o I just wanted my inspection papers! and for him to get his mitts off my car
 
It may pay you to check if you have power on the wire from the dash light first. If you do either the switch is faulty or the wire is connected onto the battery post of the ignition switch. To check this, with the ignition switched off, take the wire off the regulator and touch it to earth if the dash light illuminates that is your problem. If it doesn't the problem is in your regulator. It may be repairable but it is probably cheaper to replace it.
 
I believe the oil light would also be on if it is coming from the ignition switch as the GEN and OIL lights come off of a common wire.

Now that I'm thinking about it, all of your accessories would be powered up if the Ignition Switch Accessory Terminal had power in the off position. :eek::eek:
 
I believe the oil light would also be on if it is coming from the ignition switch as the GEN and OIL lights come off of a common wire.

Now that I'm thinking about it, all of your accessories would be powered up if the Ignition Switch Accessory Terminal had power in the off position.
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The warning lights and gauges should be connected to the ignition terminal, but the problem with these cars they have invariably all been butchered at some stage by previous owners. It is always easier to check the simple things first. The KISS principle.
 
rick55 said:
The warning lights and gauges should be connected to the ignition terminal...
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That's correct, the wiring diagram I was looking at shows the "A" terminal, which looked incorrect... I couldn't remember. But then IF he had power at the ignition terminal with the key in the off position he wouldn't be able to shut off down engine... :eek:

Mines been "Butchered" (converted to 12v) and the gauges go thru a voltage regulator and the "GEN" light is connect to the exciter wire for the alternator (has NOTHING to do with the subject at hand).:D
 
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A short update, I took a quick look at it last night, reconnected the battery, and the light is now off. Based on all of the advice above I will do some testing this weekend, starting with the regulator.

(Also off topic) Mine has been butchered a little too. Last week I found a "mystery" toggle switch under the dash below the steering wheel, with one lead connected to the ignition, and the other going out the firewall. I thought it might be an ignition cut-off, but it Doesn't seem to do anything :confused:, so its on my to-do list now! Things like these make me happy I'm an electricians son, and spent my weekends as a youth playing apprentice.:)
Thanks for all of the advice, I'll keep you posted on my findings.
 
smitchy it has been over 40 years since I had a problem with my 54 regulator.there are 3 coils in the regulator cant recall funtions exactly but I believe battery armature and field.but if the contacts stick it will turn light on and will send voltage back to generator and it will turn generator into motor.it will try to turn and hopefully flip belt before serious damage to generator.it will best case just run battery down.this may not be your problem just a heads up.best thing to do is disconnect battery if you notice this happening.in my 50 years working on them best to just install new regulator.in my opinion I would buy a nos .as I have tryed rebuilt in my day they were rebuilt NOT just cleaned and painted.now have one wire 6 volt reverse polarity alternator.way less trouble than 40 to 50 year old regulator.as I said may not be your problem. good luck p.s make sure it is for a 55 I think 49 to 55 will work as in 56 they switched to 12 volt positive ground.if no power extras windows seat 35 amp should work check generator should have amperes marked on it match regulator to amps dont forget to polarize when changing.google polarizing regulator
 
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The battery terminal relay in the voltage regulator is sticking closed when the ignition switch is turned off. Filing the points clean again may cure your problem. Best solution is to install a new regulator. A new regulator will last many years without needing to be serviced.
 
I've taken a closer look at it and I think it is the regulator. When it happened, the battery was in a discharged state, so with the battery charging circuit engaging it must have stuck.

It's working now, so I couldn't make any conclusive tests. The regulator itself looks "newer" than the other electrics, but this car has sat for about 2 years, and appears to have been driven very little for the last 6 year. I think I'll open up the regulator and clean it up. My first thought is to spray it with electronic contact cleaner.

Does anyone out there think using contact cleaner is a bad idea?
 
smitchy if reg. is new or recent you could use contact cleaner.I would not try to sand as you will create pitting which will cause it start sticking.I believe they have a tungsten coating may be wrong.tried doing that years ago with 600 grit made it worse.it probably was because battery low in your case.Y-blockhead is right my bad meant neg. ground .senility is wonderful at times:)forgot to add SSsssteamer is right on battery terminal sticking in regulator been a long time.
 
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Hi there. Look inside your regulator and you will see three relays. The left one is the voltage regulator. The centre one is the current relay which limits the generators safe maximum output in amps. The right side one is the cutout. Its like an automatic off/on switch which connects the generator output to the battery (contacts closed)when the generator is producing a slightly higher voltage than the battery which would be when the engine is revved up a little. Like wise the cutout contacts open when the engine goes back to idle or is turned off. The generator voltage in this case has dropped below battery voltage. If these contacts stick closed when the ignition/engine is off, battery current will flow to the generator and also the generator light on your dash will be "ON". This is bad because the generator armature could burn out and the battery will go flat and possibly the cutout relay and wiring could be overheated and damaged. Carefully inspect these contacts and if they are badly pitted use a points file and carefully file the high spots of the contacts and blow off gently with air. DONT TOUCH any settings, adjustments, or the other contacts. Don't use contact cleaner. If in doubt you need to find an older Auto Electrician (over 60 ) who knows about generators and how to adjust regulators with an analog test set (has needle pointers, not digital). The cutout relay is always easy to identify because the contacts are open when the engine is off. The other two relays have at least one set of contacts closed. Hope this helped you. Best regards, Kevin.
 
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