Bad Ground?
Thread Starter
Drifting
Joined: Mar 2008
Posts: 1,797
Likes: 422
From: Denver CO
Bad Ground?
After putting car back together I noticed that with no key in ignition I can tap the brakes and the center gauges will move slightly.Gauge console wasnt removed only pass side removed while drivers side was only pulled down.
Instructor
Joined: Jun 2015
Posts: 221
Likes: 13
From: Central Virginia
Yes More than likely a bad ground.
This is what you do esp with an older car.
Get a digital multimeter and set it to resistance and touch the leads together. You should get .01 Ohms or less.
Take a look at the battery's negative cable, touch one lead to the center post and the other to the lead that is attached to the center post. You should get .01-.02 Ohms. If you get anything higher than that then remove the battery lead, clean, reassemble and check again. The resistance should drop to .01.
I used the negative battery lead as instruction. Now check each and every grounding lead you can find and I mean everywhere.
Negative battery to frame where the cable connects to the frame.
Check from the frame to the body.
From the engine to the frame.
Find out where the the gauge cluster grounds to and check that.
One of the most overlooked troubleshooting procedures are in fact grounding connections. Good luck
This is what you do esp with an older car.
Get a digital multimeter and set it to resistance and touch the leads together. You should get .01 Ohms or less.
Take a look at the battery's negative cable, touch one lead to the center post and the other to the lead that is attached to the center post. You should get .01-.02 Ohms. If you get anything higher than that then remove the battery lead, clean, reassemble and check again. The resistance should drop to .01.
I used the negative battery lead as instruction. Now check each and every grounding lead you can find and I mean everywhere.
Negative battery to frame where the cable connects to the frame.
Check from the frame to the body.
From the engine to the frame.
Find out where the the gauge cluster grounds to and check that.
One of the most overlooked troubleshooting procedures are in fact grounding connections. Good luck
Is my vette stock?? HAHA
Joined: Oct 2015
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From: Im not allowed to tell you
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its normal, the amp gauge shows discharge or charge( % kind of) but it doesnt show how many amps. Its different than a volt gauge that actually has a number you can see. With your car running at idle when you turn the lights on you will see a negative deflection. Its why most people switch over to a volt meter style gauge. The amp meter doesnt really give a good indication of what is getting to the battery or health of the battery
Instructor
Joined: Jun 2015
Posts: 221
Likes: 13
From: Central Virginia
An Amp Gauge to me is invaluable. This lets me know current flow back to the battery. Yes a bit outdated but the flow of electrons is still the flow of electrons. With an amp gauge you can come pretty close to the health of a starter. If the brushes are wearing...
Last edited by usmilret; Jan 21, 2017 at 02:36 PM.
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Melting Slicks
Joined: Mar 2005
Posts: 2,093
Likes: 297
From: Midlothian VA
best gauge on the car. To OP: the amp gauge moves in relation to the charge/discharge on the battery. When the alt & bat are in good working order with the engine running you'll only see a slight charge with the needle just to the + of zero/center = life is good.
When you first start the car you should see it deflect toward + much more while the amp meter recovers charge on the battery. As the battery charge recovers the needle slowly moves back to the center. With the car off, if you turn on the headlights, or in your case press the brake pedal which ALWAYS lights up the brakes, you'll see a discharge from the battery with the needle going negative telling you that the battery is being discharged. If you're driving down the road and the gauge goes negative you know the Alt isn't charging the battery. If the gauge stays way positive all the time you know that you have a charging issue or the battery isn't taking a charge - time to check it out. All that info is MUCH better than anything you'll get from a volt meter which only tells you the voltage on the system.
Last edited by Hammerhead Fred; Jan 21, 2017 at 03:12 PM.
Thanks guys!