Wondering if I should be using 10 AWG for generator wires. Voltage regulator on firewall to generator.

the voltage regulator has BATT, ARM, FIELD leads on it. Wondering if this could be a reason GEN light is on? Wrong size wire?

Battery is new, voltage is around 13.1 when running. All is good there. Just want to know what the proper AWG size is for gen/voltage reg.

Thanks friends.

 

Voltage at battery of 13.1VDC with car running is NOT all good there. Voltage at battery w/ car running should be a minimum of 13.8VDC - closer to 14.2VDC.

 

This is why it's important to have the CSM. There exists specific troubleshooting criteria for testing the charging circuit...as an example (below). To answer your question regarding wire AWG...what AWG wire are you currently using? The color wiring diagram in the CSM demonstrates the correct gauge wiring. You have a charging circuit issue...not a wire gauge issue (most likely).

 

The great majority of Oldsmobile vehicle wiring schematics employ the following wire gauges:

Red = 10
Blue = 16
White = 20

 

Is there a way to measure the gauge of wire if its not labeled on the wiring? This is all original wiring. There are some chunks of wire from regulator to generator that look 'iffy'; somewhat burnt, some insulation getting thin as well. The BATT wire that connects the BATT terminal on the voltage regulator to the battery junction bolt is quite thick, it too is original. My Olds service manual says nothing about wire gauges or colors in the electrical part of the book.

 

Unfortunately, my service maual doesn't run you through how to troubleshoot for the GEN light being on when the engine is running. When my new battery cable arrives, i will test the vehicle when running to see what my voltage is.

 

With all devices in the car turned OFF you need to have an absolute bear minimum of 13.8VDC measured at the battery with the vehicle running. Output of the gen/alt measured at the battery is generally 14.2VDC - 14.6VDC.

The CSM demonstrates wire color and correct wire gauge.

 

I believe your car came stock w/ an OEM "generator" not an "alternator". Do you have an OEM "generator" or do you have an aftermarket "alternator"? Did you remove the VR from that car at any time? Did you remove all the wires leading to the VR at any time? If you have a "generator" & either removed the VR or had the wires disconnected from the VR for an extended period of time (2-3 weeks), did you polarize the generator at the VR when you hooked up the wires &/or the VR? The point being is if this was a very long interval of time, it may be necessary to polarize the generator (again). You polarize the generator at the VR. Based on your statement (above) "voltage regulator has BATT, ARM, FIELD leads on it" I suspect you have a generator. The generator needs to know which direction to send its output. An "experienced" generator, is one which normally would "retain" is polarity & know that direction. An inexperienced generator can lost its polarity & you may need to polarize the generator.

 

Is this what your VR looks like?

Here is a very simple video (below) of polarizing a GEN via the VR. Note the terminals will be different since the video isn't the same as your VR.

I think your VR should look like this (below).

You are actually polarizing the GEN, not the VR. You're using the VR as the location to polarize the GEN (because the VR is the grounding point in an "A" circuit). As indicated in the URL link provided (below, Polarizing The Electrical System), there are essentially two types of circuits: (1) "A" circuit & (2) "B" circuit. I believe you have an "A" circuit (used on most GM cars). "A" circuit the FIELD is grounded via the VR; and, "B" circuit the FIELD is grounded internally through the GEN.

Do this w/ the battery disconnected. Therefore, disconnect the battery BEFORE you begin. Since you already have the three wires (BAT, ARM & FLD) attached to the VR, you're fine - just leave them attached. Next, re-connect the battery. Using a simple jumper wire perform the following:

SOURCE: Polarizing The Electrical System
To polarize an "A Circuit" system, connect the FIELD, ARMATURE, and BATTERY leads to the regulator. Connect the battery. Then, momentarily connect a jumper wire between the ARMATURE terminal and the BATTERY terminal at the regulator.

 

I think I tried this before, not sure if I did it properly. Could improper polarization, or no polarization at all cause my red GEN light to stay on at all times?

 

Yes, improper or no polarization would effect the GEN light as it would indicate a fault in charging system.

I'm not sure because I'm not 100% regarding your model charging wiring circuit in terms of where the dash GEN illumination warning "indicator/switch" resides. In all likelihood, if the GEN charging system is faulty, as appears to be the case for you (your output is a paltry 13.1VDC) the GEN light would light continuously.

 

A'61 will have a generator in it, unless someone has installed an alternator.
Which seems not to be the case.
A charging voltage of 13.1 volts AT IDLE is normal for a generator.
Bring the RPM up above 1000 RPM and then the voltage should be 13.5 to 14.5 volts depending on load.
One of the main reasons that alternators replaced generators, is that an alternator would charge at curb idle.

 

Charlie - Darn good point. I forgot the delta between an ALT & GEN when charging at curb idle. If the voltage increases to between 13.5VDC - 14.5VDC at curb idle and the GEN lamp continues to illuminate however, I'd polarize the GEN at the VR as the next step.

 

The service manual should have a separate insert with a color wiring diagram as a separate page if you own an original OEM Oldsmobile CSM. The wiring diagram is in color and each wire demonstrates color & wire gauge. Here's the basics on resistance - the larger the wire, the less resistance. Therefore, a larger diameter wire has less resistance to electron flow and a greater capability to deliver wattage, voltage &/or amperage. Albeit, a larger wire is to your benefit, a smaller wire is not to your benefit. Electricity does not flow through air. If you have a break in a wire, you have complete resistance - there is no path for electron flow & no capability to deliver wattage, voltage &/or amperage. If a 10 gauge wire is designed/manufactured with 50 braided/wound individual wires inside and only one (1) wire is intact/continuous from point A to point B (49 are broken, gone, destroyed) you have increased the resistance of the wire and likely are incapable of delivering the required wattage, voltage &/or amperage. Burnt, broken, open wires need replacement. Additionally, wires which demonstrate heavy corrosion/oxidation need replacement as corrosion increases resistance and impedes electron flow. Finally, wires require clean unobstructed points of attachment free from any corrosion/oxidation. The end terminals of any wire need to be clean, if not wire brush clean (sandpaper) them to expose clean bare metal. Sometimes it's necessary to replace broken, heavily corroded wire end terminals. Any wire point of attachment needs to be free of corrosion/oxidation and needs to make solid contact with bare metal. The VR is grounded to the firewall. The attachment of the VR to the firewall needs to be clean and free from oxidation/corrosion. The end terminals of all wires must be clean & free from corrosion/oxidation.

Replace any suspect wires & clean all points of attachment. This is normal maintenance.