tim99ws6

iTrader: (31)

Here in the past few months, my car has been having some odd voltage issues. Here's the dilemma: When i first start the car, it pull sgreat Voltage(14.xxx and above). If i drive the car around, i've noticed a signifignant decrease in voltage.....Here's the catch....if i turn on the headlights, the voltage stays above 13.5......if i turn off the headlights, the voltage immediately drops below 12.5 or lower. the low voltage stays there if the DRL lights are on, or if the fog lights are on.....as soon as the drl's turn off, and the headlights turn on, the voltage picks back up????? I hope that makes sense.....


To me it seems liek a bad ground, but i admitedly am not very good with wiring. I replaced both front DRL sockets(they were corroded). The alternator is less than a year old, and I really dont think the battery is an issue......Does anyone have any ideas, or has anyone had a similiar experience????


Thanks alot guys!
Tim

JoeyGC5

iTrader: (24)

Unhook the drl's while the voltage is at the lower level. If your voltage then rises, then theres a bad drain in that drl circuit. Otherwise, the alt could be warming up and then producing less total output current. If the drl test doesn't work, have the alt checkeed out, as well as all the power wires and grounds.

tim99ws6

iTrader: (31)

Only reason i lean towards the alternator not warming up and producing less power is that as soon as i disengage the E-brake after startup, and the DRL's turn on, the Voltage drops.....does anyone have a wiring diagram that a not so experienced wirer such as myself would unerstand? Maybe a picture or something? Now that i think of it, when i turn on my blinker(especially my right blinker) the voltage flips up and down on my gauge....


If the "drain" is in my DRL, what is the process to find this "drain" and how would i fix it? I think the "drain" in my wiring is highly likely, as my car is getting up there in miles(107k), and I could see a short/drain happening in the wiring by now.....

thanks for the help

jimmyblue

iTrader: (11)

You might follow the hot lead from the alternator
around the engine bay, clean and retighten that
distribution block up by the fuse boxes, etc. Any
resistance in these kind of connections that it not
nulled by the field terminal feedback produces a
load based voltage drop. I've never looked mine
over to see where the field return comes from
but clean and tight is good. Similarly, the block to
chassis ground can rise (causing not only power
drop but sensor offsets). Try measuring block to
chassis voltage first, that is held down by just one
or two braided ground straps and screw terminals
into sheet metal. Those can easily get broken or
lost during engine bay activity, or just get crusty.

John_D.

iTrader: (2)

I don't know if alternators are still like this, but they used to have a low charge and high charge circuit a long time ago. Maybe that's changed. But it it's still that way, then the low charge part could be on the fritz, and that would explain the poor voltage with low loads. Then when a high load (headlights) kicks it over to the high charge circuit, then everything is cool again....

Probably the alternator is on it's last leg.