Battery light on

Daryl · Dec 22, 2022

cobrajeff96 said:
I'm pretty sure you don't have a grounding issue on that segment. How far away is it from the neg battery terminal?

I’d estimate it’s about 2’ from the negative battery terminal

cobrajeff96 · Dec 22, 2022

When you touch the two leads of the multimeter together when it's set to measure resistance, does the needle deflect at all? We need to first make sure that thing is zeroed if it's analog style which I think it is from recalling one of your earlier photos of it.

EDIT: disregard, it looks digital now that I skip back to page 2 of this thread.

Do you know what gauge wire it is? There might be print on the cable jacketing or there might not be. I might have to reverse my opinion on this if it's only a 2ft segment of wire. Should read zero. Been a while for me, but is there another ground cable going from battery to frame? Because if the engine (or worse, the battery) somehow is not pulling any continuity through frame material all of this might not even matter.

Daryl · Dec 22, 2022

cobrajeff96 said:
"OL" is the typical reading that there is no continuity or in other words there is an open break in the cable or there's just no continuity because of immense corrosion.

The setting all the way to the bottom-right (radio wave looking thing) will give an audible beep to let you know there is any continuity at all. Real handy for tracing wires that snake through a lot of hard to reach places but you can still find the ends of them. Alligator clips extend the reach of the leads. Or you can wrap some wire around the tips of the leads and tape them up so they don't slip off.

CobraJeff,
I did the “radio wave” setting and it gave a steady bell or ringing kind of sound.
So is that good or bad ?

ttocs · Dec 22, 2022

cobrajeff96 said:
When you touch the two leads of the multimeter together when it's set to measure resistance, does the needle deflect at all? We need to first make sure that thing is zeroed if it's analog style which I think it is from recalling one of your earlier photos of it.

EDIT: disregard, it looks digital now that I skip back to page 2 of this thread.

Do you know what gauge wire it is? There might be print on the cable jacketing or there might not be. I might have to reverse my opinion on this if it's only a 2ft segment of wire. Should read zero. Been a while for me, but is there another ground cable going from battery to frame? Because if the engine (or worse, the battery) somehow is not pulling any continuity through frame material all of this might not even matter.

that is what I was saying. When I measured the resistance of a 3 foot piece of wire in my garage I got .009-.01 ohms so .1 would mean it has 10x the resistance of my scrap piece.

when it made the beeping sound that just meant that yes the leads were shorted, it was working correctly.

You could try putting the meter on voltage and then do the same test with on lead on one end of the wire and the other end on the battery and that will tell us exactly how much voltage is being lost in that segment/how much the resistance has built up.

cobrajeff96 · Dec 23, 2022

Usually it's just corrosion that degrades the ground connection, happens over many years. Unless it's fully destroyed the ground cable all the way through it, the end points may just need a good cleaning. But it's not just the cable, it's the underside of the bolt heads that hold down the cable ends, the surfaces underneath the cable ends, the threaded length of bolt that goes into the metal, the metal itself, etc. Everything in the path needs to be conductive. Corrosion/rust will work against conductivity.

Daryl · Dec 23, 2022

I completely removed the (-) cable. It’s at NAPA for replacement.
When I touched the 2 leads together: 0
When I did ground to ground on the voltmeter: .1

The nut that holds the ground onto the engine looks in pretty good shape actually, but if I can find a new, appropriate replacement I will definitely replace as well.

Sidebar (from a previous thread of mine):
I noticed oil all over and dripping off the bottom of the Power Steering pump. That probably needs fixed or replaced.

ttocs · Dec 23, 2022

while it is off use a wire brush to clean the area that it makes contact with around the stud on the motor.

cobrajeff96 · Dec 23, 2022

Check the bolt threads too. Excess corrosion limits conductivity. When I create ground connections, I make sure everything is clean with sandpaper and then spray some shots of brake clean to knock off all the leftover sandpaper dust. After that, I paint over whatever is visible and this shields from corrosion.

ttocs · Dec 23, 2022

sand, then paint the area? I think you maybe mean after it is tightened back down with the ground in place?

cobrajeff96 · Dec 23, 2022

Of course

Daryl · Dec 24, 2022

Ok, I replaced the entire (-) battery cable, cleaned the posts and terminals, did everything else everyone said (well, except for Opal95’s exhaustive “simple” list for which I am grateful).

Result: battery light is still on :-(

badass98svt · Dec 24, 2022

Honestly, it's probably your alternator. If it's not under-charging, it may be over-charging.
You said you saw 14.6v on the meter. Granted any meter could be off by .1v or so, 14.6 is high in my opinion. Do you still have the OEM pulley on the alternator?

ttocs · Dec 24, 2022

ok well that is one thing we can cross off the list.

Didn't you say somewhere that when you turn the key on that you don't get the usual warning lights(abs normally does a cycle for example)?

lwarrior1016 · Dec 24, 2022

I had an alternator once that would charge correctly but the battery light would come on. Never stopped charging or overcharged. I finally replaced it and the shop tore my old one down. We found worn brushes inside it. When the contact was bad, the battery light would come on.

cobrajeff96 · Dec 25, 2022

Was gonna ask if the light ever flickers either at idle or when you hit the gas.

I had an alternator overspinning due to incompatible shaft speeds from a Coyote swap the first time around. That old 96 Cobra alternator couldn't take it. When at 4.5k rpm or over and I nailed the gas, battery light would strobe on and the battery would drain.

Daryl · Dec 26, 2022

badass98svt said:
Honestly, it's probably your alternator. If it's not under-charging, it may be over-charging.
You said you saw 14.6v on the meter. Granted any meter could be off by .1v or so, 14.6 is high in my opinion. Do you still have the OEM pulley on the alternator?

Yes, OEM pulley. “Newer” alternator. Never had this happen before.
FWIW, I did notice that the engine started a bit quicker after the replacement (-) battery cable. Less “lug” before it kicks over.

Daryl · Dec 26, 2022

cobrajeff96 said:
Was gonna ask if the light ever flickers either at idle or when you hit the gas.

I had an alternator overspinning due to incompatible shaft speeds from a Coyote swap the first time around. That old 96 Cobra alternator couldn't take it. When at 4.5k rpm or over and I nailed the gas, battery light would strobe on and the battery would drain.

No, light remains steady