Hey guys, I am new to this forum so I wanted to say hey first before I start throwing questions at you.

I have a 94 Chevy Silverado ext cab 4x4 with a 5.7. I am having trouble with the voltage gauge. When I turn my turn signals on the gauge bounces back and forth with the signals. When I turn on my headlights the gauge goes down. I have had auto zone check to see if the alt was going bad and they gave it a clean bill of heath. Have you guys got any suggestions?

 

Welcome to the forum,

did they also check the battery?

probably be a good idea to check the battery grounding cable, for clean solid connection.

 

Hey thanks.

No I have not check the grounding cable, I've never had a problem with it starting but I guess its worth a shot. Lets see what the wire brush can do.

 

Check the bulbs on the signal too, corrosion might be browning out the voltage or you might have a short someware.

Welcome to the forum!

 

How drastically does it move? Did this just start happening recently? Some cars do this a little normally for some reason and if you are not having any other electrical issues it is usually not worth the money to test or fix.

 

90% of the people at autozone have no clue what they ar even doing and they are lucky they can even figure out how to hook the testers up, so you cant exactly trust their word. my 92 did that a litle bit, but only at idle. Your alternator may be charging, but it could be weak, or your battery could have a dead cell. IMO check yourself with a volt meter since the GM clusters in those years didnt have the most accurate gauges in them.

 

It has been doing this now for a couple of months. The gauge does move alot (at least half the meter), its very noticable. At times it affects how bright my head lights are. If I have the heater on and the head lights the gauge reads low and you can tell that from the head lights.

 

I also have this problem with the turn signal. My gague goes way down, from 14 to about 11V. But it also fluctuates going down the road or when I put it in reverse. I have a 5speed in there. But when I take both the reverse lights out the fluctuation stops. I have gone through to make sure all my ground wires have good connection. I went as far as removing them and rubbing the surface with sandpaper. Everything should have a good solid connection. The battery is less than a month old and the ALT is less than 2 years old. The gauge has gone down to as far as 9 volts and it will turn the truck off there no matter what. I've had it shut off at 70 mph, and at 40mph... Finally got some insite from the previous owner. He said he had a wire replaced that runs under the engine along side the front of the oil pan. Don't know which wire, but I assume this was an attempt to solve the fluctuating gague problem. Plz let me know what you all know. Other than that it runs great! I rebulit the engine 2 years ago now, everything is brand new except the 2 front wheel speed sensors. I even replaced the Intrument cluster to solve the problem. It came back 6 months later.

 

Well it's not just Autozone employees is seems all the people who work at the "parts stores" now are on the verge of being idiots. Go into one and ask if the have a timing light and the first thing they ask you is what year vehicle is this for? Tell them it is for a 53 Packard and they will stand there and look at you like your from another planet. The after that they will tell you they don't know what a timing light is.

As stated before a good check of your charging system, ground wires and condition of the lights are in order, it sounds like an alternator to me but dont place money on my thoughts.

 

Hi. I am new myself. Sound to me like you have a ground to body or ground to frame problem. Disconnect and clean or repair the wire, and don't forget to spray on a good rust protector.