Charging system problems
no year stated, nor miles, nor if in the Salt belt (winter salted roads)
the dim dont lie. that is the mark of excessive of resistance.
the Head lights, dim , key off. turning them on>? when key on
heater fan , now dim,,,(got resistance)
the starter uses 100 amp, so is 10times more (at least)
if you'd had a cheap voltmeter (even 5 decades old) it had found this.
working DMM free, (dig, multi meter) makes this hard.
you will have to inspect every wire and end of every wire.
if the HL fail , ALWAYs trouble shoot that failure first.
walfart has a 10buck meter or DMM.
ill shows you the HL fix.
I turn on HL (head lights) and they are dim or dim with heater fan on.
i check battery voltage (across terms)
12v good, less bad. (not charged or bad battery)
with all loads off the battery reads 12.6v, in a warm area.
since i dont know you location or ambient temperature i can give
exact readings (and can !)
this test passes. so i connect my 2 meter leads
one to battery lug plus and other black lead to car body metal
(not engine , the body)
0.5vdc max, with HL on. if higher your body to battery ground is bad.
test 3 : this is not in random order at all..'
DMM black lead to body ground. all below checks.
(1990-1997) real Geo's dates. i only have corolla drawings,
if gm /geo didnt butcher the harness...then.....
there an engine bay fuse box. see it?
I then move my test leads as follows. (all with HL on)
the HL is on , to put a load on the system this technique, finds
weak resistive connections.
all comments for a 1996 (my wild guess) (black on body , HL on)
1: red lead to main fuse box. (this car really is a Corolla)
probe all lugs on the main fuse box, 12v it must be or you
have corrosion resistance, at any lug that is below 12v.
when we find a low reading we trace backwards to the battery
to find it. (using the meter)
between the battery plus and eng.bay box, is a FL main fuse.
"fuse link = FL"
this fuse runs the head lights directly and then goes to the main
eng.bay fuse box and runs the whole car. 100a fuse and 40 amp there
some cars have DRL (daylight running lights do you?)
by now the node (lug, terminal or pin) tha t reads low has been found
and you are posting back with year, and where it reads low.
in fact, the meter will take you to the bad spot and once found
you look at thAt part and its all green and ugly, bingo.
i posted this , instead of wild guess.
Dec 03, 2013 |
Geo Prizm Cars & Trucks