TexAg
Well-known member
This started as the Headlight Harness thread because I thought I knew where the problem was. After a few more tests, I'm not so sure.
Ok, a little more information. I built a separate harness to bypass the headlight harness.
From the VR:
I - Not used on my car
A - Directly to battery +
S - 12v power source to simulate ignition switch
F - Directly to Field on Alternator
Grounded VR to frame
From alternator
B+ post - Directly to battery +
Ground - To engine ground and battery -
Field - Directly to F on VR
I then took the following readings:
12.58v at battery posts
A and F on VR read 13v+, sometimes up to 15 or 16v.
The strange thing is that no voltage is getting to the battery. This is the same condition with the original harness?
Why would I have 13v to 16v at the A post of the VR, but then a reading on the same wire, 18 inches away only have 12.58v? I used 12 gauge wire for this test, which looks to be the same size as the yellow wire on the VR regulator plug.
When I put it under load, the results where the same, except the reading at the battery was much lower, about 12.3v.
The last strange part is that when I first started the car, the voltage at the battery climbed to about 13.2v, which i would expect, but then stopped and dropped off back to 12.58.
Could this be an alternator issue after all? I've had it tested, and it is showing proper voltage at the VR. Could it be too small? Or maybe it is intermittently faulting?
Ok, a little more information. I built a separate harness to bypass the headlight harness.
From the VR:
I - Not used on my car
A - Directly to battery +
S - 12v power source to simulate ignition switch
F - Directly to Field on Alternator
Grounded VR to frame
From alternator
B+ post - Directly to battery +
Ground - To engine ground and battery -
Field - Directly to F on VR
I then took the following readings:
12.58v at battery posts
A and F on VR read 13v+, sometimes up to 15 or 16v.
The strange thing is that no voltage is getting to the battery. This is the same condition with the original harness?
Why would I have 13v to 16v at the A post of the VR, but then a reading on the same wire, 18 inches away only have 12.58v? I used 12 gauge wire for this test, which looks to be the same size as the yellow wire on the VR regulator plug.
When I put it under load, the results where the same, except the reading at the battery was much lower, about 12.3v.
The last strange part is that when I first started the car, the voltage at the battery climbed to about 13.2v, which i would expect, but then stopped and dropped off back to 12.58.
Could this be an alternator issue after all? I've had it tested, and it is showing proper voltage at the VR. Could it be too small? Or maybe it is intermittently faulting?