Just broke out the convertible after sitting since april. The Amp guage is pegged. Voltage regulator? How do I test it?

The battery is proably low and needs charging. Charge it before you start throwing parts at something that may not be broken.

Has a fresh battery, & fires right up. even with the headlights on high beam it pegs the guage.

I'm assuming you mean it is pegged on the charge side. Is that right?

Even if the regulator is bad and the voltage is too high, a gauge pegged on charge means that a lot of current is flowing.

Unless the ammeter is faulty, you have a short.

Best turn it off and look for the short, downstream of the ammeter, before something burns up.

However, as stated earlier, also make sure that the current isn't going to the battery.

Bob

I was hoping you wouldn't say that. What could be shorted?

Boy, a lot. Forgot to ask though, what is you alternator output rating?

I'm going to back off a bit here and say it could still be a bad voltage regulator trying to overcharge the battery; or you could have a short which is draining the battery with the key off. When you say pegged, is the needle up to the C, or does it look like it is physically up against a mechanical stop?

I'd have to look at the wiring diagram, but if the regulator is causing overcharge, you will end up burning up the fusible link.
An easy test is to start the car and put a voltmeter across the battery. It's better to test the voltage across the voltage regulator directly, but if it's an overcharging problem, the battery should do OK. If the voltage reads much more than 14.5 V, or is erratic and high, it is overcharging and the regulator isn't working right. You want close to 14. Over 15 is bad.

If the charging system is good (and you should probably go to a shop and have it tested) then you may have a short elsewhere in the system. If it is downstream of a fused circuit, you will blow a fuse; if it is between the ammeter and the fuse block, you might get a fire.

Charging system first. Make sure that it really is in as good condition as you think it is.
I agree with Stumpy. A real overcharge is easy to measure, but it is best to have the system checked by a good mechanic.

Bob

thanks Bob, I'll have the shop check the voltage and give an update. Thanks Mike

Mine did that, even w/ a new battery. It dropped back after about 5-10 minutes. Still pegs at start up. I checked everything w/ a volt meter just to make sure. Start the car and check the charge at the battery. If it's 13.8 or lower you're good.

..make sure your voltage regulator has a good ground
without it will go to full field.

I've run into this many times before.

first the good news. It isn't a short unless it's a shorted field wire to or field in the alternator. Everything in the electrical system is seperated from the alternator output by a fuse or circuit breaker except the ammeter. The smallest alternator puts out over 40 amps and would blow the fuse (or trip the circuit breaker) of any thing shorted past them. If you had a short between the fuse block and the alternator output it would be a serious smoke and fire display you wouldn't miss.

Now the bad news. If you do not fix the problem you will damage your wiring & alternator.

1st. Even if you do not think it is the problem check the battery for charge. That is the first place. to start. If the alternator is really pegging (especially at idle) it probably isn't the battery but check it anyway.

2nd. Check the voltage regulator. This is probably the problem. Make sure it is getting a good ground too.

3rd. While you have the voltage regulator off check the green wire for ground. Disconnect the VR and the green wire at the alternator then check for continuity to ground. There should be none.

4th. Check the alternator for a shorted field. or just take it to AZ and check have them check it.

Now after you fix the problem check the back of the ammeter for bad insulators, check the bulkhead connectors for charred connections and be sure the fusible link isn't damaged. Many will say bypass the ammeter but the ammeter isn't the problem it's the connectors & insulators that degrade with age. I suggest replacing with larger or parralleling with another wire from the alternator all the way to the fusible link. additionally I suggest adding a fusible link at the alternator, It's safe insurance.

Assuming VR has a good ground, at a fast idle disconnect the voltage reg and if the ammeter goes slightly to the discharge side, R&R the VR. As said DO NOT continue to run it as is.

Thanks everyone. I braved driving it home from work about ten miles and started checking things.
I first put a charge on it and changed the voltage regulator. checked all the bulkhead connectors and looked at all the connections. refired it and is better but is still pushing the guage but not pegging it. I drove it tonight for about 45 minutes and looks to have come down a little more, i'll take a good look at fusebox tomorrow. Appreciate the feedback!!