need for grounds?, help please

[Schurkey]

Alright guys, I've tried everything. I'm running 17.9v and all grounds are in place, no burnt wires or anything. Any ideas?

17.9 on WHAT GAUGE?

How long has it been running at 17.9? That much voltage will boil the battery dry. You may also need a battery.

I would say the regulator in your alt is faulty. You should not be charging that high.

He's had the SAME problem with three different alternators and four regulators.

Do you have an automotive electrical rebuild shop nearby? Take your alternator there and have them bench test it.

Might try a parts store if you don't have one of those.. Years ago when i worked at advance auto we where able to bench test them. And if i remember right I think napa could as well.

Not a horrible idea...but...this doesn't test the vehicle wiring, and I bet that's where the problem is.

I had an issue with the brown exciter wire that runs from the cluster and had no charge, so I installed an self exciting voltage regulator after trying three new alternators.

If I were working on this, I'd shitcan the goofy regulator in favor of a quality OEM replacement tested in the alternator in the parts store before I brought it home, and then start tracing wires in the vehicle. If there's a problem with "the brown exciter wire" that'd be the first thing I fixed.

 

[WVBearcub]

17.9 on WHAT GAUGE?

How long has it been running at 17.9? That much voltage will boil the battery dry. You may also need a battery.


He's had the SAME problem with three different alternators and four regulators.



Not a horrible idea...but...this doesn't test the vehicle wiring, and I bet that's where the problem is.




If I were working on this, I'd shitcan the goofy regulator in favor of a quality OEM replacement tested in the alternator in the parts store before I brought it home, and then start tracing wires in the vehicle. If there's a problem with "the brown exciter wire" that'd be the first thing I fixed.

The 17.9v was what the alternator was putting out when tested at advance auto, not bench test, it was the one where they put the lead around the red wire to the battery.

The three alternators were charging 0v, there was no exciting of the alternator. That's what lead to the aftermarket self exciting regulator.

I've traced the brown wire all the way back and I see no break in the wire whatsoever. Are you saying to totally replace the wire? That actually sounds like a good idea.

My only problem is that it is my only vehicle, but I believe you just brought up my only option. I've fried two tail light circuit boards in a week.

 

[Schurkey]

Oooops. My mistake on the problems encountered with three alternators prior to the self-exciting regulator.

Do you have a "Generator" warning-light bulb in the dash? The light bulb is part of the circuit--if the bulb dies, the "brown wire" goes dead. No alternator output (unless you change regulators, as you did.)

I'm not sure of the wiring when a voltmeter is used. YOU NEED TO LOOK AT A WIRING SCHEMATIC for YOUR vehicle.

I have every expectation that 17+ volts for two months has cooked the battery, and perhaps other circuitry in the vehicle.

 

[WVBearcub]

Oooops. My mistake on the problems encountered with three alternators prior to the self-exciting regulator.

Do you have a "Generator" warning-light bulb in the dash? The light bulb is part of the circuit--if the bulb dies, the "brown wire" goes dead. No alternator output (unless you change regulators, as you did.)

I'm not sure of the wiring when a voltmeter is used. YOU NEED TO LOOK AT A WIRING SCHEMATIC for YOUR vehicle.

I have every expectation that 17+ volts for two months has cooked the battery, and perhaps other circuitry in the vehicle.

replaced bulb and even went as far as putting another cluster (out of a buddy's truck) in to see if anything changed and it didn't, still no charge.

 

[Schurkey]

Does that wire have power at the firewall connector? WHERE does it lose power?

 

[Ken K]

Alright guys, I've tried everything. I'm running 17.9v and all grounds are in place, no burnt wires or anything. Any ideas?

Ok, I have been trying to follow everything going on here. Voltage is high on AutoZone tester. dash bulb has been change, no difference, new grounds but idles better.

Can we get a digital multi meter? They are cheap to expensive but accurate. Use DMM at battery to alt. B+ terminal to see actual voltage. Still 19 vdc? OK, Check voltage at battery actual bolt or top post terminal as long as they are clean. 19 volts?
The voltage regulator is fried. Purchase what brand you want but I would use an ACDelco regulator and heat transfer grease from package. No hard to do in your garage.
The battery acts like a capacitor in the electrical system as it calms A/C voltage leakage from rectifier and read about 0.16 vAC at the battery to ground. Rev the engine up and it should not exceed 0.90 volts A/C. Triple this reading if tested t alternator, but still not above 0.90 volts A/C. Even though the battery starts, it should be tested. If bad cell or boiled with a reduced state-of-charge, will cause the alternator to do crazy stuff. I have and use a Midtronix conductance tester. It sends an A/C sine-wave thru the battery and analyzes it, when it returns to the tester.
It has been required a GM dealer since 99 to get warranty on a battery.

"Brown wire" This is turn-on voltage going to dash lamp. The peanut 194 bulb is a current limiting device. Many GM's for decades used a 460 ohm resistor in parallel with this bulb. Bulb is hot with key, voltage goes to regulator, but current is limited. Alternator turns on, produces the same voltage as supplied by the key to bulb, bulb goes out. (No potential for current to flow) Say, 12 volts on bulb, alternator is ground...lights on. Start up, alternator comes on and 12 volts got back to bulb, bulb goes out because on lesser voltage for current to flow, thus bulb is ineffective.

The resistor in parallel with the bulb, is to allow the alternator to continue to work if the bulb fails. Newer alternators with "Delta" wired stators & different regulators work internally for this function. They supply voltage to the rotor at 400 hz, as the older ones supply ground on a "Y" connect stator at 400 hz. The center tap on "Y" connect alternators where hot when working.

I do not have a wiring diagram for your pickups charging system, nor do I know what alternator you have. A self exciting alternator only turns on when rev'd up a little. I have rebuilt alternators since the 70's, but may not be your cup of tea. Fine.

GM's rule is 13.2 vdc when hot and 14.2 max hot...otherwise the battery gets it's butt kicked. So if you have been seeing 19 v, check the batteries current condition, sealed to not.

Voltage is lost across every connection, length of wire, fuse, switch, terminal and ground. So 19 volts at battery, the headlights may only be getting 17.9 volts. This will still shorten their life.

With DMM, set to dc volts, check the alternator B+ to battery terminal, while running for voltage drop. It top post, go with one meter lead on the actual post or side terminal, go to bolt. Just make sure they a clean, tight. Your reading is 0.50 vdc or less. Do the same test with the case to ground, reading should be the same. If high, like 2.3 vdc or more, bad ground from alternator to battery.
Your on a high current circuit as the system current supply split is battery to "What"? The fuse links at the starter, coming from the red battery cable to starter? This feeds the rest of the electrical system thru 3 or 4 fuse links.

Note: Use alternatorman.com to identify your alternator and purchase parts like brushes, regulator, rectifier bridge, brgs., etc.

A fully charged battery at 100% (12.8 vdc) 100% state-of-health, will only take about 0.02 - 0.04 volts to keep it changed, going down the road. The alternator does all of the rest of the work for anything turned on with electricity.

Best of luck. Old dude who hates box stuff & the "Spray & pray" parts in them. (See example of ignition module sold in 2001, 1 is ACDelco, the other is not)

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[WVBearcub]

Soldered in new regulator, now it runs low voltage, this is with nothing running, headlights or anything.

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[east302]

What is the voltage at the battery and alternator post as measured with a multimeter?

See post above from Ken.

They’re so cheap to buy, I’d go by that before trusting that dash gauge.


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[MSCustoms]

Did anyone check and make sure the brown wire is in the correct terminal pin at the alternator? Call me paranoid but couldnt the previous owner have moved that wire when trying to fix it?

 

[WVBearcub]

Did anyone check and make sure the brown wire is in the correct terminal pin at the alternator? Call me paranoid but couldnt the previous owner have moved that wire when trying to fix it?

There's only one wire on the plug, the brown one.