View Full Version : Weird Electrical Problem
07-12-2010, 06:40 AM
I have a 2000 Ranger XLT 4 Cyl 2WD Ext Cab.
I recently had to replace the Alternator, Battery and the fuse for the Alternator in the Fuse box under the hood. I replaced it all and everything appeared to work fine. Now my battery light is flickering at speed and comes on at idle. The Battery gauge never moves from right in the middle of H and L.
I rechecked the connection on the Alternator, rechecked the fuse and not sure what else to do.
Whether I have the lights, A/C or anything else on doesn’t really seem to make a difference one way or the other.
That said... My questions are what could the problem be and how can I figure out what it is?
07-12-2010, 07:18 AM
my money is on bad alternator, is it brand new?
as far as i remember, and i could be wrong on this, the light comes on, when the amprage is too low for what the demand is, and the h/l needle is more or less voltage... so the alternator could be producing 13 volts, and keeping the needle high, but the regulator? that's built into the alternator may be fried, and not putting out the amperage... i would take the alternator off, and take it into a parts store to be tested
also, why did all of those items need to be replaced? battery and alternator AND fuse, sounds to me like something shorted out and blew the whole works, with that much damage, it is possible something else is fried...
07-12-2010, 07:48 AM
It all started out as a bad alternator and the new one is a "new" rebuilt one from Advanced. Originally I replaced the Alternator and the battery light was still on and the H/L gauge was low so I replaced the battery. Replaced the battery and got the same thing, I finally realized there was a 30amp fuse replaced it and all was fine. It was probably just a bad alternator that blew the fuse, I just left the new battery in because I'd already bought it.
No way I can test the Alternator without taking it off the truck? And, if it's bad wouldnt the light come on and stay on?
Thanks for the response
07-12-2010, 09:46 AM
Possible to test on the truck? Yes, but do it right ...
Remove the alt and check it off the truck.
The light may be getting borderline current/voltage to keep the light off, so it may flicker at one rpm, and light up solid at another. Power output is a function of alternator rpm.
You should also check the battery. If it is bad, it will pull too much from the alternator and not leave enough for the system.
07-23-2010, 05:04 AM
if you get a full test system you can test the alternator, but i've only seen one in my life (never delt with electronics when i was doing mechanics) and it was when i was in highschool, in my shop there, and the machine was ancient, it's more or less just a glorified battery tester with leads that go everywhere on your truck, and still doesn't completely isolate the alt from the rest of the system... much easier to just pull it off the truck and take it in, plus then you know you are getting the right reading...
07-23-2010, 08:02 AM
just a hunch but there should be a single wire i think it is gray or maybe the connector is grey. it plugs into the alternator. check to see if that is loose or has a bad connection. maybe you can fiddle with it and see if the bat light changes..
08-17-2010, 04:39 AM
sorry to dig this back up, i haven't been online in a while...
that's a good point, i know gm alternators were really bad for a connector comming lose and the alternator not working properly as a result
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