Is it my altenator ?

DaveMarcotte · Post by **DaveMarcotte** » Sat Sep 03, 2016 6:27 pm

After dropping my engine back in after a rebuilt I'm having battery charging issue. Went for a 30-45 min drive with lights on. After parking for an hr I When to take my wife to pgo for a nice lunch but not enough juice to start. Noted that I had a 50/50 change at getting the yellow and gray wires correcton when reinstalling the alt, I believe I got them wrong and corrected. Charged the battery right up, started her up then checked alt on my charger which said low voltage? My cars a 77 but relay set up is the same as a 76. I removed the block of relays and regulator to clean the engine bay when to engine was out. Could I have done something there wrong? Regulator has a gray and orange wire. Gray connected to the closer connection to the front of the car. Any advise or trouble shooting I should try is much appreciate!!!

narfire · Post by **narfire** » Sat Sep 03, 2016 9:21 pm

What I did was bump start the car and then at around 2500 rpm put a multi meter + on the stud on the alternator and the neg on my intake. It should read between 13.8 and 14.2 V I believe. Mine read 9.4 so bought another volt reg for $12.00 swapped it out and all is good.

spider2081 · Post by **spider2081** » Sat Sep 03, 2016 9:25 pm

I think you have a remote voltage regulator mounted on the fender welll

I also think this is close to the wire diagram for your car.

Here ia a simplified wire diagram of what I believe is your alternator circuit

Hope this helps.
I could not find a diagram showing where each relay is located but you can identify your relays by the wire colors on the diagram.
Basic circuit operation of the light is: The light has voltage on one side of it as soon as the key is turned on. The ground for the light passes through the normally closed contact of the "battery charge indicator relay" to light the light. When the engine is running and the alternator is working the yellow wire brings voltage from the alternator to the relay coil. the relay disconnects the ground from the "battery charge indicator" in the tach. So the light goes out. The Voltage regulator supplies voltage to the alternator to control the alternators output. You should measure battery voltage on the grey wire at the alternator with the key in the "on" position. The ground for the charging system and the headlights is made at the voltage regulator mounting bolt.

DaveMarcotte · Post by **DaveMarcotte** » Sun Sep 04, 2016 3:36 pm

With engine running: multi meter on battery 12.25 v. At alt gray wire almost nothing .4. Is that a slam dunk that alt is done?

ORFORD2004 · Post by **ORFORD2004** » Sun Sep 04, 2016 4:05 pm

You should have 13.5 at least. 12.5 is battery only

DaveMarcotte · Post by **DaveMarcotte** » Sun Sep 04, 2016 4:09 pm

ORFORD2004 wrote:You should have 13.5 at least. 12.5 is battery only

So basically nothing from the gray wire which goes to the regulator means shot altenator? Or is there another possible explanation?

Thanks

spider2081 · Post by **spider2081** » Sun Sep 04, 2016 5:48 pm

The voltage regulator puts voltage on the grey wire to make the alternator work. Your next test is to check for voltage at terminal 15 of the voltage regulator. If you do not have voltage there go back to fuse 10. Fuse 10 is the tenth fuse from the steering column. I am pretty sure the ignition switch has to be on for fuse 10 to have voltage on it.

DaveMarcotte · Post by **DaveMarcotte** » Sun Sep 04, 2016 7:05 pm

spider2081 wrote:The voltage regulator puts voltage on the grey wire to make the alternator work. Your next test is to check for voltage at terminal 15 of the voltage regulator. If you do not have voltage there go back to fuse 10. Fuse 10 is the tenth fuse from the steering column. I am pretty sure the ignition switch has to be on for fuse 10 to have voltage on it.

nothing on term 15. 124.5 v at the the fuse?

spider2081 · Post by **spider2081** » Sun Sep 04, 2016 7:48 pm

so does terminal 15 of the voltage regulator have an orange wire on it?? I am pretty positive that terminal 15 has to have battery voltage on it for the regulator to work. The regulator has to be working for the alternator to work. So first there has to be voltage on terminal 15 and that voltage passes through the regulator to terminal 67 with the grey wire on it. So with the key on both the terminal with the orange wire and the terminal with the gray wire should have battery voltage on them. Once the engine is running and the alternator is working the Orange wires voltage should increase to close to 14 volts and the grey wires voltage should decrease as the battery charges and the load on the alternator goes down.

DaveMarcotte · Post by **DaveMarcotte** » Sun Sep 04, 2016 8:09 pm

spider2081 wrote:so does terminal 15 of the voltage regulator have an orange wire on it?? I am pretty positive that terminal 15 has to have battery voltage on it for the regulator to work. The regulator has to be working for the alternator to work. So first there has to be voltage on terminal 15 and that voltage passes through the regulator to terminal 67 with the grey wire on it. So with the key on both the terminal with the orange wire and the terminal with the gray wire should have battery voltage on them. Once the engine is running and the alternator is working the Orange wires voltage should increase to close to 14 volts and the grey wires voltage should decrease as the battery charges and the load on the alternator goes down.

Yes 15 orange wire. No voltage with key on. Car on nothing on either. ?? Thanks

spider2081 · Post by **spider2081** » Sun Sep 04, 2016 8:48 pm

Let me clarify what you are saying.
Your have voltage on fuse 10 with the key on and also with the engine running.
You do not have voltage at terminal 15 of the voltage regulator and terminal 15 does have an orange wire on it.
If this is what you are saying:

Have you looked behind fuse 10 to see if the orange wire is connected there as the print shows.
Does the alternator out light light in the tachometer when the key is in the on position.

DaveMarcotte · Post by **DaveMarcotte** » Mon Sep 05, 2016 8:30 am

spider2081 wrote:Let me clarify what you are saying.
Your have voltage on fuse 10 with the key on and also with the engine running.
You do not have voltage at terminal 15 of the voltage regulator and terminal 15 does have an orange wire on it.
If this is what you are saying:

Have you looked behind fuse 10 to see if the orange wire is connected there as the print shows.
Does the alternator out light light in the tachometer when the key is in the on position.

You nailed it!! The orange was disconnected! Must have been when I messing around there looking for turn signal. While I have your attention. Right in the area near the fuse there are two violet wire going to one with a male connector not connected to anything. Any ideas. Thanks for all your help so far you've saved me at least a new alt

DaveMarcotte · Post by **DaveMarcotte** » Mon Sep 05, 2016 8:32 am

I should've mentioned that no lights ever light on the tack

spider2081 · Post by **spider2081** » Mon Sep 05, 2016 9:27 am

Great that you stuck with the process and figured the orange wire problem out.
I am simply guessing but attached to the left side if the pedal assembly is a socket for a service tight to plug into. I think there might be viole wires that go to that socket. These sockets are troublesome. the plastic brakes and they short out causing fuse to blow. Maybe someone with a similar car could chaek that or post a photo for you

Is it my altenator ?

Is it my altenator ?

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