I have 12,7 volts across the terminals where you plug in the fuse. I have performed a dark test for amps. half 1/2 amp. I took out the GEM module and the generator power from the terminals on the bottom of the high power distribution box.
Hi,
I’d listed (2) tests (B & C) that may not be feasible at this point, we can work around them numerically, using your information posted..
0.5 Amp isn’t an overly large draw for these vehicles, > 1 Amp is more a concern. What amount of time does it take for your 100% charged battery to reach a discharged state? (Properly functioning charger verified ).
For clarity, you took a Series measurement with your VOM between the battery post and it’s removed terminal to acquire the 1/2 Amp (0.50) reading, as indicated?
A. Battery voltage sits at 12.7VDC across the battery terminals?
B) If the alternators charge measured with your VOM across the terminals is not between 13.3-13.8 volts, I’d have its output tested.
B1) What is the vehicle’s warm idle, Voltage across the terminals when idling?
Running underdrive pulleys?
Serpentine belt squeal?
B2) Have someone bring the RPM’s to 1,000 & hold, voltage across the terminals change?
B3) If yes, have the RPM’s brought up to 1,500...2,000, locate it’s peak VDC & @ what RPM.(?)
C) Bring the battery in for a load function test.
D) What battery Mfg & P/N# are you running, how old is it?
.E) Verify All Pos.& Neg. terminals in the charging system are clean, non corroded & solid. Use Noalox or another electrical connection grease. Replace any questionable connectors.
F) Running an aftermarket stereo head unit with a remote triggered Amp & Subwoofer(s), Factory?
G) An aftermarket alarm system installed (working or disconnected)? Factory?
H) Checked the dwell on your interior light, verify it turns off?
(I) Check your compartment lighting & ensure the lights are triggered off? Trunk, Hood, etc..
J) Did this issue start worsening over time, or suddenly? Drive the car daily, more of a weekend car, or seasonal..recently pull it out for the year?
If it occurred suddenly, any recent changes made to the car, mod’s?
Good luck!
-John