Since I bought my 69 chevelle the battery guage hs never worked. I have the ss dash with the tach surrounded by the fuel, battery, oil and temp guages.Today I crawled uder the dash and did some testing. All of the other guages had a hot and ground wire going to them. I tested the wires to the battery guage and they were both 12v. Is this right? Can't find the issue in my wiring diagrams. Both wires disappear into a harness and I can't trace them. Anyone know how the battery guage is supposed to be wired?
Battery guage wiring issue...
jonh1373
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Since I bought my 69 chevelle the battery guage hs never worked. I have the ss dash with the tach surrounded by the fuel, battery, oil and temp guages.Today I crawled uder the dash and did some testing. All of the other guages had a hot and ground wire going to them. I tested the wires to the battery guage and they were both 12v. Is this right? Can't find the issue in my wiring diagrams. Both wires disappear into a harness and I can't trace them. Anyone know how the battery guage is supposed to be wired?
It really depends on the gauge and the wiring. If you have the old style with a heavy wire running THROUGH the guage, both sides will read 12 Volts as the gauge samples the current that passes. I think we need more info.
Is it a stock or after market application?
do you know if the guage is in series with a 12 Volts line (it sounds like it)?
Chuck
Is it a stock or after market application?
do you know if the guage is in series with a 12 Volts line (it sounds like it)?
Chuck
The guage of wire looks to be about 14ga. I don't know if original to the car, but obviously original 69 chevelle euipment. When wires are detached from the guage, both read 12v idependently. Here are photos of front and rear of guage. Wires are off of the battery guage. What else can I provide that will help?...Jon
http://i251.photobucket.com/albums/gg320/jonh1373/DSC02097.jpg
http://i251.photobucket.com/albums/gg320/jonh1373/DSC02101.jpg
http://i251.photobucket.com/albums/gg320/jonh1373/DSC02097.jpg
http://i251.photobucket.com/albums/gg320/jonh1373/DSC02101.jpg
it appears that you actually have a ammeter gauge which the wiring has 12 volts batt. + coming in and then goes out to the the voltage regulator or alt( not sure which off the top of my head) it supplies batt. + voltage there. if everything is working perfectly you probably wont see much movement on that gauge. but if the battery were drained down some from leaving the lights on or something like that it should show a negative value then when the car starts it will show a positive value as the alt.is charging the weak battery back to normal value.the higher +(C) value, the more amps from the charging system and the lower -(D) value the less amps from charging system. a little above center on gauge with engine running is typical normal value
The needle soesn't move at any time, no matter what condition the battery is in. I suppose the guage/meter is bad. I would think if I upped the voltage to the meter it should at least jump if it was working. any other way of testing it that anyone can think of??
Most early Amp meters are wired in a parallel shunt configuration, meaning that most of the current passes by the meter, through the shunt, and the meter is calibrated so that the meter movement, which requires almost no change in current or voltage, shows the actual amount of current, sampled off the shunt, while not having to deal with that current through the meter itself. It is possible that the meter movement is bad but the shunt is OK. I'd suspect the meter.
I have to tell you though, John, my 67SS has a full guage set up including an Amp meter and I hardly ever see movement because the regulator, if working well, almost kills all the movement. You will see the movement if the alternator doesn't work but not often if everything is OK.
Chuck
I have to tell you though, John, my 67SS has a full guage set up including an Amp meter and I hardly ever see movement because the regulator, if working well, almost kills all the movement. You will see the movement if the alternator doesn't work but not often if everything is OK.
Chuck
Read this thread where I helped another member with 69 gauges, post back if you have other questions.
This explanation usually makes people crazy, but according to the diagram posted by undee, the "battery gauge" is measuring the voltage across the "battery charging wire" right above where it says radiator in the drawing from MAD. Since this is the voltage measured across a 6' copper wire, the voltage should be quite low.
If the system is running off the alternator and charging, the the needle swings in the C direction due to the voltage being slightly higher at the horn relay. Running off the battery swings the gauge toward D.
Try measuring voltage with a DVM from each side of the gauge to the same ground point. Also measure the voltage across the gauge itself (not to ground). The difference in the first 2 readings should be equal to the last.
Next measure from the horn relay to the junction block. This value should be the same as the voltage across the gauge. If it is, it suggests the gauge is bad.
Of course, this is based on the accuracy of the drawing, so buyer beware...
If the system is running off the alternator and charging, the the needle swings in the C direction due to the voltage being slightly higher at the horn relay. Running off the battery swings the gauge toward D.
Try measuring voltage with a DVM from each side of the gauge to the same ground point. Also measure the voltage across the gauge itself (not to ground). The difference in the first 2 readings should be equal to the last.
Next measure from the horn relay to the junction block. This value should be the same as the voltage across the gauge. If it is, it suggests the gauge is bad.
Of course, this is based on the accuracy of the drawing, so buyer beware...
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