How many wires is the alternator pigtail supposed to have?

["Turbo-T"]

Long story short....recently took the TR on a 900 + round trip. 80 miles from home the alternator starts working intermittently. It recently started working again before I could get it home so I was not able to diagnose if it was a faulty alternator or if the sensor wire lost charge.

When i looked at a schematic, it looks like there's 3 wires coming off the alt: 1 batt charging wire, another red wire and the brown pigtail wire.

On my car there's the brown pigtail wire all by itself and then there's the batt charging wire. That's it.

I'm more used to working with GM's 10SI alternators. They require a 12 v. source to turn on the alternator, then there's the volt wire that turns on the volt light on the dash, and then the batt charging wire.

So that has me wondering how many wires off the alternator are there supposed to be?

Thanks!

 

[Rodney87GN]

On my car there's the brown pigtail wire all by itself and then there's the batt charging wire. That's it.

That's what mine has and is what it should be.

When i looked at a schematic, it looks like there's 3 wires coming off the alt: 1 batt charging wire, another red wire and the brown pigtail wire.

I believe that is for the other model Regals VINs A and Y. My schematic for the VIN 7 still shows 2 wires coming off the alternator (brown and red batt wire).

 

["Turbo-T"]

I believe that is for the other model Regals VINs A and Y. My schematic for the VIN 7 still shows 2 wires coming off the alternator (brown and red batt wire).

The scematic I used (Chiltons) showed this for the turbo 6 cars 84-87.

If there is only 1 wire pigtail, is the alt. internally self excited? Or ?

 

[novaderrik]

The scematic I used (Chiltons) showed this for the turbo 6 cars 84-87.

If there is only 1 wire pigtail, is the alt. internally self excited? Or ?

must be a generic wiring diagram. the 84/85 cars used a 12SI series alternator with the flat plug, and the 86/87 used the newer CS style alternator with the rounder weatherpack style connector- but i think they still used the same two wires.
when i upgraded my 84 to a CS alternator from an 88 Grand Prix, i wound up with two wires going to the plug- the red one that looped to the main lug on the back of the alt (which goes directly to the battery) and the brown wire that goes to the volt light in the dash. as it worked out, i didn't even need to swap my alternator- the problem was a bad connection on the plug where the cluster goes in the dash. i figured it out because i noticed that the volt light never came on with the key on/engine off, but if i'd push the cluster in, the light would pop on and it would charge to a solid 14.5 volts when i started it instead of a slow and steady drop when the light didn't work.
so, the moral of this story is to check to see if your cluster is getting a good connection in the dash. if it's loose, then pop the cluster out to clean the connections with a pencil eraser and gently bend the tabs up a bit so they make better contact.

 

["Turbo-T"]

I've checked my voltage with the car running and it varies from 14.0 to 13.4, sometimes getting as low as 13.1 vdc.

When the volt light was on it was 12.4 to 11.8

I got my volt readings from the Scanmaster.

 

[Rodney87GN]

The scematic I used (Chiltons) showed this for the turbo 6 cars 84-87.

If there is only 1 wire pigtail, is the alt. internally self excited? Or ?

Here's the schematic straight from the factory service manual.

 

["Turbo-T"]

Thanks.

Hhhmm.....perhaps the battery charging wire serves as the "turn on" wire?

Perhaps I should invest in one of these?:Casper's Electronics, Inc.: Field Fix Harness 1986-1989 GN/TTA

 

[novaderrik]

I've checked my voltage with the car running and it varies from 14.0 to 13.4, sometimes getting as low as 13.1 vdc.

When the volt light was on it was 12.4 to 11.8

I got my volt readings from the Scanmaster.

get an actual voltmeter that you hook directly to the battery- i'm not saying the scanmaster isn't accurate, but i'd personally rather have an independent verification.
does the volt light come on with the key? what is your battery voltage with the engine off? does it go up when you start it?
you've checked all of your connections, right? even something like a bad engine ground can cause things to act funny.

 

["Turbo-T"]

Batt reads 12.5 with ignition on and 12.7 off.

At the same time the Scanmaster read 12.3 with engine off, key on.

Volt light currently does not come on if key is on and engine not started. Not sure if it was the same when the alt wasn't charging and then came on after engine was running....or what.

 

[novaderrik]

Batt reads 12.5 with ignition on and 12.7 off.

At the same time the Scanmaster read 12.3 with engine off, key on.

Volt light currently does not come on if key is on and engine not started. Not sure if it was the same when the alt wasn't charging and then came on after engine was running....or what.

there's your problem- if the volt light doesn't come on, then the alternator is getting "turned on" by the ignition switch. on my car, i was able to get the light to come on just by pushing on the bezel around the cluster to get a better connection- and my volt meter hooked directly to the battery showed that the alternator was charging after doing that. but i knew it wasn't "fixed", so i pulled the cluster and fixed it right
it takes like 5 minutes to get the cluster out- just make sure you take the shift indicator cable off the column before pulling the cluster, or you will break it. just pull the cluster out, clean the connections, bend up the tabs in the plug in the dash, and put it back together. i'd wager that everything will work perfectly, and you will only have 1/2 hour and no $$$ into it.
i did this to my T Type, and since it worked so well, i decided to see if i could fix the odometer on the digital dash in my 94 Caprice the same way. and, yes, it did the trick there, too.

 

["Turbo-T"]

Derek I am confused. Are you saying that you think the volt lamp is not making a secure enough connection and thus allowing the alternator to not work right?

How is the alt getting turned on by the IGN switch if the light doesn't come on? Where is it getting turned on from?

 

[Rodney87GN]

Derek I am confused. Are you saying that you think the volt lamp is not making a secure enough connection and thus allowing the alternator to not work right?

How is the alt getting turned on by the IGN switch if the light doesn't come on? Where is it getting turned on from?

Yes that's what he's saying. I scanned the circuit operation from the service manual rather than typing it all out. But basically that stupid little bulb does a lot for the system and is pretty important.

+1 also for checking the connection on the instrument panel.

Hope that helps a little...

 

[101prf]

just make sure you take the shift indicator cable off the column before pulling the cluster, or you will break it.

Is this on all gn's. I have this problem and need to pull mine.

 

["Turbo-T"]

Is this on all gn's. I have this problem and need to pull mine.

I think it's only on column shifted cars with the shift indicator on the dash.

 

[101prf]

Thats what I thought but mine has tension trying to pull it out, so I figured better to ask then find out the hard way!