About Us

aloha69gto · 03-14-2006, 01:08 AM

Ok I have two wires on the + side of the battery. One goes to the starter the other goes to the alternator. I have a plug in the back of the alternator with two wires going to it. I read 12 volts at the battery when the car is off. When I start the car it drops to 11.87 or so. Not the 14.4 I should be getting. At least thats what I have been told I am supposed to get. When I turn the key on I get the gen light nice and bright. When I start the car it goes really really dim. I swapped the alt. today and had the same result. What might the problem be? Isn't there supposed to be a ground coming from the back of the alternator? And what does the little plug do because it seems it dosen't do anything. The car will start and the gen light will come on with it plugged or unplugged. I am so ignorant when it comes to wiring. Any help would be appreciated. ALOHA

aloha69gto · 03-14-2006, 05:52 AM

Ok found the search button. LOL So the plug is for the regulator right? What else goes to the reg? I looks like several things but I dont know what. If the reg is not working how is everything else working? And how is it powered?Just so I am on the right page. Battery ground goes to block. Positive goes to starter. Smaller wire from starter comes up and goes to harness by alt. One wire goes from Positive to alt. I removed that wire from battery and No power to anything. Car would not start. Does this sound like a correct wire harness? George you sound like the king on this. whatcha think? Thanks

george kujanski · 03-14-2006, 10:04 AM

So you've got a 69 GTO...do you have the original alt/reg or a later model alt with internal regulator?

Obviously it's not charging because bat volatge when running should be about 14 volts. Let me know what system you have & we'll go from there.

George

aloha69gto · 03-14-2006, 12:14 PM

yeah it is stock. There is a external voltage regulator.

engineer · 03-14-2006, 01:37 PM

take both alt to auto store and have them checked.

george kujanski · 03-14-2006, 06:31 PM

With the key on, what happens to the idiot lite when you unplug the two- wire harness at the Alt?

Measure the voltage at the reg term 3, it should be at battery voltage all the time, key on or off.

Measure the voltage at the reg term 2 with the engine running, using the AC volts function, it should read 7 to 10 volts AC.

Measure the voltage at term 2, key off, using the DC volts scale.

Report what you find..

aloha69gto · 12:03 AM

I am getting power to the reg at 3 but not getting 7-10 volts ac and .20 when the car is off in dc. I also installed a new regulator today. Light dosent come on when I turn on the key only during starting even then it is real dim. I am so confused.

george kujanski · 03-15-2006, 12:45 AM

Originally you said that the light was bright when you turned the key on, now you changed regulators and the light does NOT turn on with the key on?

Let's start by checking the alt. Pull the two wire plug, start the engine and jump the "F" terminal of the alt to battery positive. The output voltage should go to 16 volts or so.

The "R" terminal should have 10 to 12 volts AC or so at the same time.

If that's good, check the continuity of the wires; the "F" wire from the alt connector to the reg term "F" and the wire from the alt connector term 'R" to the reg term 2. There should be very little resistance in the wires, end-to-end.

If all that's ok, I'd say temporarily use the old reg, connect the wires, turn the key on, the light should go on. Pull the connector out from the alt and the light should go out or very dim.

Let me know.

George

aloha69gto · 05:02 AM

Ok seems the alt is good.I put a new one on yesterday and had the same results.When I jumped the f wire to the batt I got the same. Am I supposed to take the alt power wire off? If I do that the car gets no power. I check f and it is good. I put the old reg back in. pluged reg plug back in. Turned key on took a sec but gen light came on real real dim. started car when staring the gen light got brighter. when started gen light goes back to real real dim. The power wire to the alt is good. Also when I have the key on and hit the brakes the dome light dims. And the backup lights are stuck on. I am still trying to locate the switch and where it connect to. As well as the turn signals are not blinking, however when you turn on the flashers they flash, and the dome light flashes. Also when do little lights the side of the vallance come on? Sorry to flood you guys with all my problems, but you will be rewarded with mai tai's and coconut bra's. I am starting to pull my hair out. George you need a trip to Hawaii. LOL

aloha69gto · 03-15-2006, 05:13 AM

I think I might have it figured out. I can't seem to find a ground strap from the engine to frame. The only one I found is the small one on the passanger inner fender. Could this be the root of all my problems?

george kujanski · 03-15-2006, 10:25 AM

The engine is connected to the battery negative thru the large cable. The frame and the rest of the body needs to be connected back to the battery negative also and that is usually done thru the ground straps that connect the engine to the frame, engine to the firewall, etc.

The goal is to make sure every piece of metal has a good electrical connection back to the battery negative. Since the body is sitting on rubber cushions, it needs ground straps from the body to the frame, to the engine, etc.

Once you get your grounds back, see if you still have wierd operations with your lights. If so, you may have some other wiring problems to chase down.

Speaking of grounding, make sure the regulator metal case is grounded well to the firewall; use star lockwashers under the mounting bolts to bite into the metal for a goood electrical connection, AND a ground strap from the firewall to the engine.

There's nothing mysterious about the charging system; assuming the alt and reg are good, the two wires between the alt and reg need to be good, reg term 3 needs to have a good battery connection, and reg term 4 needs to be connected to the idiot lite.

Once you know the alt is good, and the wiring is good, we need to check the regulator operation.

I'd like to go to Hawaii......my wife doesn't want to sit on a plane that long. I'll need to do some convincing...

George

aloha69gto · 03-16-2006, 01:15 AM

well.. I dont know. I grounded the engine to the firewall still no dice. I am really confused. new reg, all the wires seem to be ok, and I believe the alternator is ok. Even though when I jump f to + and checked voltage I only got 11.8 but when I put the alt on I got the same. So I put the old alt back on and returned it. Reg is getting power. Any ideas george?

george kujanski · 03-16-2006, 11:56 AM

Hold on now...... If you pulled out the plug from the alt, then ran the engine and jumped the alt "F" terminal, ON THE ALT, to the battery positive, and still measured only 11.8 volts at the alt output, your alternator is not working. period.

What that does is turn the alt fully on, bypassing the voltage regulator. Voltage should jump up to 16 volts or so.

Make sure your belt is not slipping.

BTW, you shouldn't need an additionl alt ground,the it's done thru the mount.

Do that test again as I described.

George

aloha69gto · 03-24-2006, 11:40 PM

Ok got a new alt today. Put it on and same thing. They tested it at the store. I put the alt on and connected everything. Checked voltage at batt. 11.67. Disconnected plug at back of battery and got something silly like .6 but the power wire was still hooked up. Should the power wire be connected during these tests?

aloha69gto · 03-25-2006, 11:33 PM

I got it!!!!!!!!!!!!! The damm plug on the back of the alt was wired backwards. Such relief.

george kujanski · 03-26-2006, 01:38 AM

But a mystery remains.......you said that when you jumped the alt field to the battery (full field) you still got only 11.8 volts when you should have gotten 16 or so. If you did the test correctly a good alt should have output about 16 volts.

George

aloha69gto · 03-26-2006, 06:52 PM

I know I don't understand??

george kujanski · 03-27-2006, 02:14 AM

IN any case, it's good that it's working.

Since you said the connector was wired incorrectly, how did that happen? Didi you buy the car that way or awas it a simple mistake?

George

aloha69gto · 03-27-2006, 05:59 AM

I bought the car like that. I just got it shipped here and I am going threw the car to make sure everything is perfect. The plug clip was cut off and it slides right in. Well someone cut the clip off so they could insert the plug upside down. Why someone would do that is beyond me when all you have to do is pull the connectors out of the plug and reverse them. Thats why I have been stumped about this whole thing because that is the last thing I would check. Anyway thanks for your help George.

Menu

About Us