76 possible electrical problem

[beermanpete]

Try running the car without the voltage regulator (unplug it). If the battery voltage is now 12 volts the regulator is bad. If the voltage is still too high unplug the 2-pin connector on the back of the alternator. If the battery voltage is now 12 volts there is a wiring fault. If the voltage is still too high you have a bad alternator.

[bhermes]

Checked car at idle again and got about 14.5V. Unplugged the external voltage regulator and got 12.3V.

What if the wiring from alternator to voltage regulator has a problem would this occur or just if the regulator is bad?

Does it make sense for the alternator to put out this kind of voltage (17-18V)? Other posts may have indicated it should not.

This forum is great and really helping me so keep up the support. I learn quickly but no very little.

[bhermes]

Also, can someone just educate me a little on fuseable links? Not sure where they are and what all they do. Any chance this is the issue?

Thanks.

[bhermes]

A little more information. At high rpms (1500-2500) the radio with the voltage regulator unplugged, is staying on. In otherwords apparently the voltage with the regulator unplugged is not exceeding 15V. I did not have help to actually read the voltage at the battery.

A little clarification from the previous post. When I check with the 2 pin connector on the alternator unplugged should I also have the voltage regulator unplugged or should I try that with the regulator plugged in.

I am still concerned that I have replaced all of these parts at least once which would have led me to beleive that there is a wiring or another problem.

Additional help would be appreciated.

We are almost there.

[beermanpete]

Checked car at idle again and got about 14.5V. Unplugged the external voltage regulator and got 12.3V.

Good. This means the alternator output stops when you unplug the regulator. Your regulator is bad. Try another new regulator.

What if the wiring from alternator to voltage regulator has a problem would this occur or just if the regulator is bad?

If the wiring has a problem the alternator would still over-charge when you unplug the regulator.

Does it make sense for the alternator to put out this kind of voltage (17-18V)? Other posts may have indicated it should not.

Yes. The alternator is capable of putting out 60 amperes. This will easily raise the battery voltage to 18 volts or more if it gets the chance.

This forum is great and really helping me so keep up the support. I learn quickly but no very little.

[5thhorsemann]

First, the alternator will put out 18V+ AC at full field. The regulator converts the AC voltage to DC voltage and regulates the voltage to around 14 volts max.

Second, pull the plugs one at a time.

Third, wire in a cheap voltage gauge under the hood, across the battery terminals so you can rev the motor and watch what the charging system is doing.

Fourth, Fusable links are modified fuses built into the wiring harness as a last resort failsafe. You have to really screw up or have a dead short to pop one, the links aren't your problem, they would have the effect of no voltage as opposed to high voltage.

Just because a part is new doesn't mean it is good, take the alternator to a shop and have it tested if it makes you feel better, but I still think your regulator is shot, a bad externally regulated alternator will usually show low or no voltage.

[beermanpete]

Also, can someone just educate me a little on fuseable links? Not sure where they are and what all they do. Any chance this is the issue?

Thanks.

A fusible link is a short piece of wire used as a fuse. Typically this wire is smaller that the wire it protects and has flame retardent insulation. If there is a short or other over-current event the fusible link melts and opens the curcuit just like a conventional fuse.

The fusible links are located on the relay bracket just in front of the battery. They are the short wire loops that are attached to plastic connectors. There is also one that is part of the wiring that attaches to the positive battery terminal.

In your case this is not the problem. If a fusible link was bad your car would not run, the headlights would not work, or some other accessory would not work.

[bhermes]

Two is enought to convince me. I will pick up the voltage regulator at NAPA on Saturday and install. Just need to hope the shop that installed the original regulator takes it back.

Thanks for all the help and I will let you know what happens.

[bhermes]

Last thing before installing the new regulator and this may be stupid. Is it possible that I have a internally regulated alternator hooked up to a external voltage regulator? Can you tell by looking at the alternator? I assume that this may cause issues.

Just want to confirm before I get stuck with two voltage regulators. Not a big deal but the $100 could be spent on beer this evening.

[SteveJ]

Last thing before installing the new regulator and this may be stupid. Is it possible that I have a internally regulated alternator hooked up to a external voltage regulator?

Yes.

Can you tell by looking at the alternator?

No. You can find out by measuring about 17 or 18 volts at the battery with the car running.

I assume that this may cause issues.

Yes. We told you that before.

[bhermes]

SteveJ, first of all I would like to thank you for staying with this issue. I have learned alot and I think we have found the issue. I am a little confused with your last post. I have 17-18V at the battery at 1500 rpms with my extrenal regulator connected. I then unplugged the regulator and the voltage reduced to 14V. We concluded that this meant that the external regulator was bad. Would the same senerio occur if I have an internal regulated alternator hooked up to a external voltage regulator; with 17-18V with all hooked up and 14V with the extrenal unplugged. Meaning that the extrenal regulator is not bad just that I have two regulators in play. I am sure your last post and previous posts have answered this question but just having trouble pulling this last piece of information together.

[SteveJ]

SteveJ, first of all I would like to thank you for staying with this issue. I have learned alot and I think we have found the issue. I am a little confused with your last post. I have 17-18V at the battery at 1500 rpms with my extrenal regulator connected. I then unplugged the regulator and the voltage reduced to 14V. We concluded that this meant that the external regulator was bad.

To be perfectly clear, I didn't respond to that part of the thread. My earlier responses were that you had both internal and external regulators.

Would the same senerio occur if I have an internal regulated alternator hooked up to a external voltage regulator; with 17-18V with all hooked up and 14V with the extrenal unplugged. Meaning that the extrenal regulator is not bad just that I have two regulators in play. I am sure your last post and previous posts have answered this question but just having trouble pulling this last piece of information together.

The only time I ever had both regulators at play was about 11 years ago. I replaced the alternator in my 73 and while testing the addition of relays to the headlights, one of the headlights burned out. I checked the voltage at the battery with the car running. It was 17 VDC, so I quickly shut the car down and started researching the issue online. I quickly realized that I had an internally regulated alternator, so I followed directions online and jumpered out the circuit for the external regulator. I never at any time experimented with running the car with just the external regulator unplugged.