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Senior Contributor
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Discussion Starter · #1 ·
Fighting the electric.

Symptom: car wouldn’t start just a click.

Jumped it and it started.

I Checked that the battery, it was good and recharged it. Car started but when I turned on the headlights the amperes gauge goes negative. Step on the gas and it stays negative.

Pulled the battery cable and the car dies.

Pulled the alternator and took it and the spare to the auto store and had them checked..... both are AOK

Replaced the dubious ground strap on the alternator prior to putting it back and checking the tension

Started the car and the pulled the battery cable the car died.

Suspect the voltage regulator. What is a down and dirty way to check it? Hopefully with out a lot of fancy meters that I don’t have either. I am going to try and just replace it tomorrow but would like to know how anyway.

Noticed that the resistor wire gets hot when the key is turn to the on position even though the engine is not running. Should it be warm to hot to the touch normally?


Staring at the cobbled together wiring harness and hoping that it is not the problem in STL.
c
 

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Opeler
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343 Posts
Had a similar problem.

Basically the charge is not getting from the altenator / generator to the battery. I had done away with the separate regulator and gone for an all in one self regulating alternator / generator from a later opel (it was new).

Anyway, I had loss of charge and flat battery plus negative amp gauge reading. The altenator / generator became hot where it was holding the ampage and not sending it to the battery. Mine turned out to be the triode (diode) pack which is essentialy a part of the internal regulation system. Replace the triode, works fine now. I would suspect if not wiring, it is definateley your regulator.

A word of warning, the guy in the repair shop said that you should never run the unit without the leads connected to it, as it will build up power and cook itself.

It actually transpired that this is what had happened to me. The bolts on the rear of the unit had worked loose, causing disconnection, thus cooking the triode.

Its great to see that there are still alot of knowledgable people out there, who bother to take the time to repair such units rather than replace the whole thing.
 

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Senior Contributor
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Discussion Starter · #4 ·
Hmm well the battery is fairly new say 750 miles on it.

I am going to replace the voltage regulator today as advance autoparts has them. It seem advance has lots of Opel part in the KC MO area because every part that I have ordered from them has come from a shop in KC and not the warehouse in Tenn.


Thanks for the heads up on the triode (diode) pack.

I have found that since I have already taken the trouble to remove the part I might as well try to fix it without a total swap if possible or practical.

Learned that with starter brushes back in the 70ies. Back then $45 for the starter (a week's pay at min wage then) or $3.78 for brushes.... it was a no brainer…


I just hope it is not the wiring...

BIG QUESTION How hot should the resistor wire be to the touch when car is running correctly?
 

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I pulled my dash- checked ALL the wiring against my official 71 Opel wiring manual, checked the bulb, checked the wiring from the alternator to the voltage regulator. Everthing checks out OK, but that damn alternator bulb WILL NOT light up. Previously took it in to Auto Zone and had them run a test on the charging system where they told me that it was charging OK, but no light on the alternator. Now from previous posts, I understand that if the bulb doesn't come on then the system is NOT charging. I will do anything to get this fixed as it has been bugging me for two years. How can it be charging if the bulb is not coming on? I am suspect of the voltage regulator and the battery. The battery looked ancient when I got the GT and continously needs recharging. The voltage regulator is an ebay purchase and is held together with duct tape. Don't know what to do but I want that DAMN LIGHT ON. Any ideas out the in Opel land
 

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I'm not following you on this. The light at the gauge comes on with low voltage or nothing coming from your alternator. Is it not on with the car not running and key on? The light is just idiot light for people who don't look at the gauges. What does your gauge show and are there any symptoms besides no light? If that is it, the ground wire is my first thought.
 

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Opel Junkie
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113 Posts
checking the regulator is fairly easy to do. with the key on, and the car not running, you should be getting about 12 volts dc at the field wire. if you are, then the voltage regulator is working; if not, the regulator is bad.

next, start the car and check voltage from the alternator...i have found the cigarette lighter to be a good place to check. you should see more than just battery voltage if the alternator is putting out, i.e. 13.5 +/- volts output, while battery is at 12.5 or so.

if you only get battery voltage at the lighter socket, try checking right at the alternator. if the voltage output is good there, then you will have a wiring problem. if voltage is not good, replace the alternator.

good luck, hope you figure it out. i would hate to see you spending precious $$ when you don't have to.

mike
 

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nobody said:
I'm not following you on this. The light at the gauge comes on with low voltage or nothing coming from your alternator. Is it not on with the car not running and key on? The light is just idiot light for people who don't look at the gauges. What does your gauge show and are there any symptoms besides no light? If that is it, the ground wire is my first thought.
There are two lights on the oil pressure/ alternator gauge. With the key on but not started the oil pressure light comes on OK but not the alternator light. When the key is turned to the start position and the car started, the oil pressure light goes off and pressure shows on the gauge-BUT nothing is happening on the alternator side of the gauge. It was explained to me that the light MUST come on in order to activate the alternator system- no light -no charge and no movement on the gauge. My light does not come on even though all the wiring is correct per the manual and the light bulb is good. checked for continuity through the whole charging system and it all checks good. Am at my wits end on this thing.
 

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The only two things I would suggest:

1) It doesn't happen that often, but a light bulb can fail with a "shorted filament". A simple quick check will show bulb continuity with this type of failure. Did you actually power up the bulb and confirm it actually lights up?

2) If the bulb is OK, then the current that should be going through the bulb is going else where due to a parallel path. It's possible that there is a connection (short circuit) across the two points where the bulb goes. This will allow current to flow to get charging system working, but since it's not flowing through the bulb it wouldn't light. A simple way of checking this is remove the bulb and fire up the car. If it still behave the same way then there must be a short across the bulb terminals somewhere.
 

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Charging indicator "idiot" light . . .

ALL first generation, externally or internally regulated alternators relied on a "tickler/exciter current" circuit to "start/kick off" the regulator and cause the alternator to charge. This single wire (Opel = blue/white) circuit has a light bulb (charge/alt idiot light) connected in series to provide a small current to start the charging action of the alternator.

Turn the ignition key "on" and current flows from the regulator connection (slightly negative in relation to the switched 12V at the ignition switch "run" contact), through the idiot light to the ignition switch "run/on" contact. This completes the circuit for the bulb and causes it to come on. When the engine starts and the alternator begins to "charge", this raises voltage to an equal state with the ignition switch contact and the light goes out.

IF the idiot light does NOT come on with the key, there is no "exciter" current flow to the alternator and it never goes into a "charging" state. That's it!
 

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the alt light never goes on in my opel, the original bulb was bad so I put a good spare in but it still wont go on, could it be the voltage regulator?
 

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I used a volt meter and the bulb socket is hot when the key is on so that almost might check off any other problems but the bulb wont light, is it a strange bulb that I won't be able to find? can I also substitute another bulb from my extra guage panel?
 
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