Came back from long trip, car rode fine except shortly before end of trip I hit a pothole and the ANTI LOCK light came up in the message center ( turned car on and off, but doesn't go away, topped fluid, assume it is sensor, will have to look at it on lift )didn't drive car('89 Coupe) for a day...started it, noticed heater panel readouts weren't on ( assumed it was the 28 degree weather effect)...went 5 miles, stopped car, alarm went off when opening door, closed door, tried to start, DEAD! Left alone for 1 hour , tried again and it started. Went 5 miles, signl lights weak, voltage reading 8-9 volts while running, got home, stalled....DEAD!!!!
Suspecting new alternator was bad, I got another in exchange, replaced 1 year old battery, still nothing....voltage is 12.2 while riding, 11.9 at idle.If I diconnect heavy red alt. wire voltage reads the same.?? Is it possible that ANTI LOCK is at the root of problem, could there be a short in the headlight switch, is there a relay for the light alert buzzer... car was PERFECT before ALL this happened.
FRUSTRATED and need help.Suggestions????
Thanks in advance!

 

You could have shaken a couple of things loose. Check your battery connections. The ABS light may have gone on because a sensor was knocked out of whack. Check the wheel that took the brunt of the pothole and make sure everything is tight there too.

 

I'm not an electrical genius, but I will try to provide some guidance. Since I don't know the year of your vette, I will offer general suggestions. If you know how to access DTCs (diagnostic trouble codes), you should do so. As a rule, it is preferred not to replace components (alt., batt.) until they have been proven faulty through tests. I understand the urgency to remedy your electrical problem, but don't let frustration blind your reasonable thought process.

From the voltage readings provided, it would appear that your electrical system is experiencing a "short" in one, or more, of it's components. As you are aware, the alt. output should read 14+ volts dynamic, and the batt. should read 12+ volts static.

If the DTCs don't indicate an obvious problem, you might connect an ammeter to the positive cable of the batt. and determine if there is an undue current draw. If the current draw is excessive, you can connect an ammeter to the positive batt. cable, and then remove fuses one at a time to try and isolate the source of the current draw. When the ammeter indicates a reduction in amperage flow when a certain fuse is removed, this will indicate a possible problem source.

 

Good Advice :iagree:

 

The pot hole damaged the ABS wheel sensor. The fusible link on the alternator output is open and should be replaced (but check it first). Charge your battery up, it is discharged. Low system voltage will prevent your heater a/c control from working.

 

Measure the voltage output to the heavy red wire at the alternator.

I suspect the fusable link in that wire is burned out; it's located in the end of the wire near the junction block behind the battery.

 

I would check the voltage output directly at the alternator. It should be in the 14 volt range even at idle. Then check it at the battery. If there is a significant difference you need to start hunting for loose connections that are causing the voltage loss.

 

Jumped wire from alt. to battery to by-pass fusible link, but still no difference in voltage! Do not have ammeter.
Let car run and watched voltmeter as I pulled fuses, one at a time...no change. Tried to bring to mechanic ( 1 mile away) battery died just after I lowered window to get gas, car died. With battery out, all OTHER fusible links look good! ?????¿¿¿¿¿¿¿

 

Try charging the battery up, start the car and disconnect the battery (while it's running). If it dies, the alternator isn't charging. You may have gotten a bum alternator.

 

Your alternator has no output and the red battery symbol on the dash should be lit which indicates no charging by the alternator. Charge your battery up and you will be able to start your car. Look at the condition of the terminals on the plug that plugs into the alternator. Good electrical connection is required or the alternator will not work. With the ignition on, the red wire on the alternator plug must have 12v on it or the alternator will not work. If you have 12 v on the red wire, have the alternator checked.


[Modified by jfb, 8:30 PM 3/11/2003]

 

Brand new alternator, no red battery light on ( yes, it works), battery fully charged,started car, jumped alternator directly to battery to by-pass burned fusible link ,if there was one, alternator terminal FINE....NO Charging going on!!!???
Thanks for everyone's help....frustrating!!!!!

 

If the charge light is not coming on, disconnect the voltage regulator connector and with a fused jumper, ground the brown wire with the ignition on. If the indicator comes on the altermator is bad. If it doesn't come on the brown wire may be open, the light could be burned out or there might be an open from the gauges fuse wire (pink/black) to the indicator. Check all wires in the regulator harness for a battery voltage with the ignition on, particularly the red wire which is on another fusible link to the junction block. I'd also pull the conduit off the harness from the alternator to the junction block and check the condition of each wire. If the insulation has worn through on any of these wires, it could easily short out the regulator ruining the alternator. There is no relay for the warning chime. I previously posted it's power and grounds.

 

Is there too much here that is COINCIDENTAL? Could one of these problems ( i.e. ABS, headlight alert, heater controls, alternator ) be at the root of ALL of this??
One pothole started all this trouble!

 

Sun Cr:
re: "I previously posted it's power and grounds"

Could you elaborate on this, I don't understand, and can't find where you posted power and grounds.

 

Your link "Dead in the Water". Note pink/black wire is the ignition signal from the gages fuse to the alarm module indicating the engine is on & to turn off the lights on alarm. It shares a splice with the low charge light and a host of other devices including the ABS module relay. As to the low charge light, its path is completed by the brown wire at the voltage regulator. Something appears to be removing power from this circuitry (and based on your symptoms it's probably before any splices) as your Vette is losing the ignition signal which is turning on the alarm (and because it comes on, power to the alarm module which is through the courtesy/clock fuse means that circuit is ok); it doesn't have a charge indicator light, its got an ABS light on and it may be frying the regulator which is essentially turning off the alternator. Suspect worn insulation in the gages fuse circuitry before any splices; (though this scenario should blow the gages fuse), a faulty ignition switch or its circuitry not only to the gages fuse but from the battery since the car quits running; the red power wire to the regulator which is also protected by a fusible link behind the battery, or still perhaps worn insulation on the charge wire itself. I'd dig into the harness from the regulator/alternator first & make sure that a fusible link hasn't opened now (obviously they were ok earlier, because the replacement alternator got it up & running; albeit temporarily), and check for a nicked wire. This harness is much more accessible; it's not blowing fuses and it's a more probable place for worn insulation with plenty of metal around to cause a momentary short to ground. This could fry the alternator, and when the battery discharges below 9 volts, the engine dies.

 

Just remembered, also check the integrity of the connector at the regulator making sure none of the pins are touching. This is best accomplished by using a DVM set on the resistance scale or if it's so equipped, setup for a continuity alarm. You'll need to remove power from the red wire first, so disconnect the battery. Place one probe on a pin and the other probe on the pin next to it. Wiggle the wires. If you get continuity, the connector is bad.

 

Latest chapter...Checked continuity through all fusible links by battery, all fine!
Checked for frayed or cracked insulation, fine!
Checked pins of connector at reg...fine!
Checked continuity to ground on all connections, only found cont. to grd. on 14 and 16 links with ignition “ON” ...all else ...none
14 and 16 seem to be headlights and instr. panel.

Any thoughts...thanks for all the input!

 

Is there any hope left???

 

Ok, disconnect the battery completely and measure the resistance from the ground terminal to the frame or engine of the car. It should be less than an ohm.

If all of the positive connections are good, you need to start looking at the negative cables.

 

I'll take the long shot here and go for one of the most simple things.

The pothole jarred an internal connector between plates loose in the battery.

The alternator won't charge or give any output because there's no field voltage.

Try another battery or charge the one you've got and then turn on the headlights. If they open up and come on bright and stay bright for 5 minutes or so then it's NOT the battery.

When you jump it off the alternator is receiving +12 volts from the donor vehicle which may get the alternator charging. Car should run until you turn it off.
At his point I'm going to guess bad battery since you've already changed or checked everything else.
Good luck with it.