94 f150 running rough, battery light on dim
09-08-2010, 11:50 PM
#12
Senior Member
Hopefully it helps - sure can't hurt! Mine was in the same boat when I first got it - replaced the battery, plugs, cap, rotor, wires, battery, you name it. Didn't really get any results until I replaced the battery leads - then it was a night/day difference.
09-09-2010, 12:00 AM
#13
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Do you think a fuse could be causing a problem like this? Its dark out now so I haven';t checked any of them
09-09-2010, 12:02 AM
#14
Senior Member
did u take the positive cable off the battery wile the truck was running???
if it turns off then its ur alternator..
i blew 3 alternators because of my sound system! had to take it to a friend to build me a big one..
if it turns off then its ur alternator..
i blew 3 alternators because of my sound system! had to take it to a friend to build me a big one..
09-09-2010, 12:03 AM
#15
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No I didn't do this but i tested with the multimeter while the truck was running and its putting out 14.1v.. so wouldn't that mean the alt is ok?
Also what if I cut part of the insulation on leads open and stick my multimeter in there? testing it that way would show if its the leads thats the problem wouldn't it?
09-09-2010, 12:06 AM
#16
Senior Member
im not sure..but it doesnt hurt to do it...and it doesnt take long..
turn the truck on and take the + of the battery...that happened to me a couple of times and it always came back to the alt!
turn the truck on and take the + of the battery...that happened to me a couple of times and it always came back to the alt!
09-09-2010, 12:08 AM
#17
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with your meter, you'll want to test terminal to terminal. Cutting the insulation will just give you a visual idea of how much corrosion is creeping down the wire inside the insulation.
If you get new leads, spend a buck on some dielectric grease and put it all over the terminals. That will help keep them from corroding again.
If you get new leads, spend a buck on some dielectric grease and put it all over the terminals. That will help keep them from corroding again.
09-09-2010, 01:14 AM
#18
DO NOT remove the battery cable with the truck running, that's an excellent way to fry the alternator. The alternator isn't designed to run the truck, it only charges the battery. The voltage spikes can and will fry it.
It sounds like you have a bad ground. When you have a bad ground it finds a ground wherever it can, and weird things happen. On my car I had a bad ground and all my dash lights would illuminate dimly, the high beam indicator, the blinker indicators, etc.
It sounds like you have a bad ground. When you have a bad ground it finds a ground wherever it can, and weird things happen. On my car I had a bad ground and all my dash lights would illuminate dimly, the high beam indicator, the blinker indicators, etc.
09-09-2010, 01:26 AM
#19
Senior Member
it wont fry it...if the alt is bad than the truck will just turn off if its good it will keep on and u know its not the alt...and if it keeps on then just put the + right back..
ive done it to check my truck a couple of times..and its worked for me
ive done it to check my truck a couple of times..and its worked for me
09-09-2010, 01:39 AM
#20
^^^ You got lucky. Read the installation instructions that come with new alternators. In bold print it says "DO NOT INSTALL UNLESS THE BATTERY IS FULLY CHARGED OR ALTERNATOR DEATH MAY RESULT." You used to be able to test alternators that way but not anymore.
