How do I tell if my voltage regulator went out?

Mine's in the computer, not on the firewall.

My battery is good for sure, checked it today. But the amp gauges takes a beating when I press the brakes or use any power source. Runs down REAL quick. So either the Regulator is bad or the Alternator is bad...

If I run an "autozone" type test on the alternator... can I verify if the regulator is out? or will it just say basically "bad alternator"?

I don't want to install the external voltage regulator if the alternator is my problem. I'm on a tight budget right now.

If the regulator is the problem, does anyone have part numbers they've used and/or a wiring diagram or which wires to tap into for power? The write up in the Tech section is helpful, but kind of basic.

Thanks

 

Find the green wire at the alternator. The regulator controls the
voltage/current by grounding this wire. It actually does it repeatedly
to maintain the proper voltage.

Testing the alternator is simple. Just tap into this wire somehow and
ground it. But don't do it for very long, just long enough to see how the
gauge reacts. If you get a lot of voltage showing, then the alternator is
OK. If not, then something is wrong with the alternator.

Of course, make sure the engine is running during the test.

If the voltage goes high during the test, most likely the regulator is bad.

When the alternator tests bad, many times it's just worn brushes. It's a
cheap fix, only a few bucks. Once in awhile, you'll run into bad diodes.

-Maurice

 

I just removed my alternator, took it to the local alt/starter shop and they said it was fine but the brushes had slight wear. They replaced the brushes for $20.

Got home, re-installed the alternator, cleaned all wire contacts, and cleaned up the battery terminals, cables, wires, and all grounds.

Fired it up and the gauge is still reading low.

I've read the Tech post on the external voltage regulator about 10 times and still can't grasp it.

Does anyone have a quick drawing or diagram of the external regulator mod for the '92-93 trucks?

 

Ok, I just ran outside and probed into the green wire...fire up the truck made various ground contacts and nothing happened on the gauge.

When the key is in the "ON" position, my gauge reads normal just past the 2nd bar to the left (battery has been charging) but as soon as I start it up the gauge drops down to the 1st bar on the low side. If I turn on the lights, it drops more...same with A/C, stereo, blinkers.

 

Ok, before you do anything, check the connections between the engine and the PCM, make sure they are making contact. Also check the ground straps that they are in place and contacting.

All that done you can add a regulator to it from an earlier Dodge, like a 71, 318, pickup truck. The wiring is already in a thread, run a search, probably on regulator. There are only two wires and a ground wire.

 

I think I would check for a short in the system or possibly the intake heaters may be stuck on, try unplugging them and see if you have the same problem....? Just a thought, may be worth checking, doesn't sound like a regulator problem unless it is shorted out inside.........??

 

Jeremy, didn't you just have problems with the crank sensor? Does your A/C clutch engage when you turn on the A/C? If not the crank sensor isn't working yet. If that's OK, try swapping the ASD relay (sends B+ to the field in the alt when the PCM gets a crank signal) with the A/C clutch relay to eliminate the possibility of a burned out ASD relay. There are 3 relays on the diver's fender, ASD is front, starter is center, A/C is rear. Also check the contacts in the ASD relay plug, mine were dirty and causing charging problems.

 

wv smoker is right about the heaters. They will draw enough power to
make it look like the alternator is not working.

Once you've verified the heaters are not activated, check to see if there
is battery voltage at the blue wire to the alternator while the engine is
running.

DO NOT ground the blue wire, just test it with a test light or voltmeter.

To summarize, the blue wire supplies power to the alternator field while
the engine is running and will always show battery voltage. The green
wire is controlled by the regulator, grounding it will cause full output
of the alternator. There should be two more wires that are larger than
the blue and green wires. They are probably both black. One goes to
ground and the other goes to a fusible link which carries the output of
the alternator back to the battery. Make sure there are no blown fusible
links.

You can check these two larger wires at the alternator. With the engine OFF,
one will test negative and the other will test positive. If no positive, the fusible
link is likely blown.

-Maurice

 

check crank sensor

 

Crank sensor is good. I've pulled it 3 times. Soldered all connections.

I pulled the ECM, cleaned the connection.

I'll disconnect the intake heater and go from there....

I'll try swapping the ASD relay with the A/C relay and see what happens.

If no progress there I'll test the other wires on the alternator.


Thanks for the help guys...always appreciated.

 

Before you start swapping parts, does the A/C compressor kick in? If the A/C is not kicking in that means that the PCM is not getting a crank signal, the charging system will not work either. I know you've repaired the wires, but is the gap set right? (0.050", use a brass feeler gauge) If the PCM doesn't get that crank signal it will not energize the ASD relay and the truck will not charge.

 

had the same problem with mine...... went to all the trouble of bypassing the voltage reg. in the computer toputting one on the firewall. did not work. The problem turned out to be a worn and corroded connection on the battery. The more amps you draw the hotter the bad connection gets wich in turn creates resistance . So check all your conections first before replacing things

 

had a similar prob.it turned out to be a corroded factory splice it was on the front left fender in a y splice it was 2 #20 or 22 ga. white res wires spliced onto a red #12 wire took 2 whole days and nights to find but I must say I know of a least 4 other people who had the same prob.very poor des. by the dodge boys.

 

My dad's 90 model voltage regulator would crap every once and a while. The voltage gauge would read anything and the battery would go dead. A new Napa regulator on the firewall and a auxillary ground from the voltage regulator on the firewall to the intake took take of the problem.

My friend at Dodge said, "Dodge reccomended the new ground to prevent anymore regulator issues." It worked!!!!

Good Luck

 

I just unplugged the heaters...no change.

I just swapped ASD relay with A/C...no change.

I just gapped the Crank Position Sensor to .050"...no change.

I'm gonna run down to the parts store before it get too dark and grab some new battery terminals and some ground wire...see if that does anything.