I'm having trouble with my 82. I put new belts on all, and a new alternator. I have good charge going from the alt. and to the main harness under the hood. The Battery is receiving the charge, but still the alt gage will not rise and the red lite "batt" is on. Any ideas?
Thanks.
Chuck

 

you should have a volt meter in the dash, what does it say?
Do you have a regular voltmeter? If so, what is the voltage at the alternator and battery with it running and stopped?

 

How do you know the alt. is charging correctly, if the gauge is not working?

 

I use a volt meter at the regulator and check output. lots of juice. Then I use a volt meter at the battery, lots of juice. It is the meter in the dash that isn't wanting to work. It was, and then nothing, I tapped on the glass and it worked for a moment and then went dead. Now when I start the car the meter comes up a little and then stops rising. I'm just not familure with the circut board that is used on the back of the gages. Do they go out often? Oh and by the way, I made a mistake on the year, it's an 81. Don't know if one year would make that much diff. but maybe.
Chuck

 

OK, you've given me enough info to help you, I think. Since it "worked" a bit when you tapped on it, I believe that one of the coil wires has broken off of its mounting terminal (inside the gauge). You can fix it, if you want to try...you really can't lose anything, as you would be replacing it anyway. Of course, you have the fun of removing the gauge cluster [if you're not sure on that, ask for instructions below]. When you get the gauge out, first check to see if the gauge works; use a small 1.5v battery and touch the two terminals on the gauge. Just touch it while you watch the dial and then immediately remove them. If the needle moves, the gauge is OK and something in the wiring leading to the gauge is wrong. If the needle doesn't move at all, you will need to open up the housing to get to the coil wires. Pull off the needle by lifting up on the center section..DO NOT PULL ON THE NEEDLE ENDS. You may need to pry the center hub up with a plastic tool a little at a time. Then [if I remember right], you will have to drill out the two rivet heads on the dial face...be careful not to scratch or damage the dial face as you will be re-using it. You only need to drill a short distance (about 1/16") to get the heads off and use a drill size just larger than the shaft of the rivet (not the head). SAVE THE REMAINS OF THE RIVET HEADS. Now look in the case where the two winding wires should be soldered to the mounting posts. I'm betting that one of them is broken off. If not, the winding is likely internally damaged and you will need to replace the gauge. If you find a broken wire, you will need to resolder it. That thin copper wire is insulated on the outside with shellac, so use something to strip/scrape the insulation off about 1/8" back from the end. If the wire will reach to the terminal, use a pencil type soldering iron to reattach it; if it won't reach, find a short length of small wire and jumper it to make the connection. Be sure that the "bare" wire areas are not going to short out against the dial face or case when you reassemble it. Now, put the dial face back on and use some liquid epoxy at the rivet areas to 1) hold on the dial face; 2) hold the old rivet heads in their original place; and 3) fill the hole in the rivet heads. Let the epoxy harden, paint the heads with some Krylon semi-flat black paint, put the needle back on (you don't have to press hard to get it on), then use the battery to try out the gauge. If the wire was broken, there's a 95% chance that the gauge will work just fine. If so, install and drive away happy. If not, order a new one from your favority Corvette parts supplier. [The process description is longer than it will take to fix the gauge, by the way.]

 

Thanks for the help 7t1vette. I will print out those instructions and try. I do have a new meter on the way. One from ebay that didn't cost much. I'll keep you posted. Thanks again.
Chuck

 

7T1Vett:
There are three posts on the back of the gauge I bought on e-bay. I took a regular 1.5 volt D battery and used a couple junper wires to do the following: I touched the two main posts with the leads and got nothing. The third post that looks like a ground, the other two are on some sort of an insulator. When that third is touched with one of the leads, and the other is to the post on the right, I get a slight movement of the needle on the gauge. When the third is touched to the other post I get nothing. Is this sounding likt a good gauge to you? And also, the water temp gauge and oil temp gauges don't look like they are working. Can I use the same test on them before I go to sending units? I'd like to get this all straight in my head before I pull the cluster. I hate to not have this car to drive in the nice weather.
Thanks for your help.
Chuck

 

Check your 20 amp gages fuse also the 20 amp choke heater fuse and for an open in the brown wire coming from term 1 on the alternator.

 

check my threads, "Alternator Overcharging" and go thru all of them. I has similiar issues and went thru everything...thanks to the help of forum members. My problem is finally fixed and I learned about the entire charging system. Just be aware that you may have to take the gauge cluster out. Good Luck!

 

Out of curiousity where is the ampmeter guage needle supposed to "rest" on a healthy charging system with the engine running? (78-82)

 

78 - 82 has a volt meter not an amp meter
should read around 13volts. They are not very accurite at all. I would use a Real volt meter Fluke 77 or equivilant and measure the voltage at the alternator and compare that reading to what the in dash unit says. Put a piece of pin stripe tape on the gauge face for the readings you want to see

 

Mine pegs over to the edge on the right side of the guage in the picture...it's not in the red...but right at the edge of the white line..14 volts maybe?





I'll check it at the alternator

 

That is ok, Like I said, use a real meter to check the alternator output and check it against the in dash meter for a comparison. If you take the little hash mark betwen 13 and 18 to be half way or 15.5v its reading a tad high, but I would about bet the alternator actual output is closer to 14.75 and the error is in the meter

 

I would love to pass on the favor and help that I received on my alt gauge problem. Search the post on Alternator Overcharging for any additional info. Hope it helps you....it solved my problem. Good Luck