Alternator or voltage reg?
Logistics Pro
Joined: Aug 2003
Posts: 4,701
Likes: 6
Once started, mine sits to right of center, and when you kick on the heater blower, lights, etc, it goes even further right. The turn signals is the most obvious indicator because the needle fluctuates with the pulsing of the signal light(to further right of center) I think my system is slightly overcharging, and with a load the regulator lets more through to compensate, but it is too much. Could this be correct?
Postmaster
Joined: Jul 2005
Posts: 3,248
Likes: 0
A quick test, with a voltage meter, check the voltage of your battery, log it down. Start the engine, and check the voltage at the battery, log that down. Then turn on your blower motor and head lights on, and check the voltage at the battery, log that down. Then rev your engine to 2000 rpms, lights and blower motor off, check the voltage at battery and log it down. Post your results.
Purpose for test is to isolate if the problem is mechanical or electrical.
_______
Buck
Purpose for test is to isolate if the problem is mechanical or electrical.
_______
Buck
Logistics Pro
Joined: Aug 2003
Posts: 4,701
Likes: 6
Well, it took me a few weeks to get to the truck, but here's what I got.
Off 12.49V
Off w/lights 12.10V
On idle 15.2V
On w/lights 15.6V
On w/lights& blower 15.5V
At 2000 RPM
Lights & blower 15.84V
Lights 15.7V
Just running at 2000 RPM 15.2V
According to my ford manual, there is either a bad ground connection between alternator and voltage regulator, or bad ground between regulator and engine. Which wires in the harness are these? Can I just ohm them to find out if there is a short, or do I need to read them while connected?
Off 12.49V
Off w/lights 12.10V
On idle 15.2V
On w/lights 15.6V
On w/lights& blower 15.5V
At 2000 RPM
Lights & blower 15.84V
Lights 15.7V
Just running at 2000 RPM 15.2V
According to my ford manual, there is either a bad ground connection between alternator and voltage regulator, or bad ground between regulator and engine. Which wires in the harness are these? Can I just ohm them to find out if there is a short, or do I need to read them while connected?
New User
Joined: Nov 2005
Posts: 23
Likes: 0
does your bat go dead or nearly dead after letting it set over night if so mostlikly the regulator alternators dont just usually just go bad they start to get weak and then go bad ussually the regulators go those trucks are know for that a buddy of mine had same problem took alt in to napa had it tested ok then replaced regulator fixed prob
Logistics Pro
Joined: Aug 2003
Posts: 4,701
Likes: 6
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Cargo Master
Joined: Oct 2004
Posts: 2,148
Likes: 0
From: Seneca, SC
even new parts can go bad, or be bad from the manufacturer. A voltage regulator typically isn't too expensive and trying another one might be worth your time. Anybody think the GM alternator needs a GM voltage Reg?
Logistics Pro
Joined: Aug 2003
Posts: 4,701
Likes: 6
The gm alt has an integral VR. That is the beauty of it. No wiring draped all over the place. Anyway, I am sick of messing with it, and the parts store won't take back electrical components, so I don't want to be buying VRs that "might" be good.
New User
Joined: Jan 2008
Posts: 0
Likes: 24
Depends what it is 
It is also getting harder with all the off shore companies.
Ignition Modulators = Motorcraft
Voltage Regulators = Motorcraft or Standard
AC-Delco (yes, I know GM) but they are of better quailty than some Taiwan parts.
It is also getting harder with all the off shore companies.
Ignition Modulators = Motorcraft
Voltage Regulators = Motorcraft or Standard
AC-Delco (yes, I know GM) but they are of better quailty than some Taiwan parts.
Last edited by Mil1ion; Nov 30, 2005 at 06:03 PM.
Senior User
Joined: Jan 2003
Posts: 176
Likes: 0
From: Addison,Texas
<i>The gm alt has an integral VR. That is the beauty of it. No wiring draped all over the place. Anyway, I am sick of messing with it, and the parts store won't take back electrical components, so I don't want to be buying VRs that "might" be good.</i>
Is the integral GM voltage regulator in circuit with the GM alternator and Ford VR?
ash
['That would be exciting.']
Is the integral GM voltage regulator in circuit with the GM alternator and Ford VR?
ash
['That would be exciting.']