alternater

[Warren 86 ranger]

the light on the dash stays on for the alternater but if i rev up to 4000 rpm it goes away my battery is never dead i dont have any electrical problems so wy is it on??

 

[martin]

If the alternator is externally regulated it might be a bad connection at the regulator box or somewhere else along its route between the two.

 

[fomoco83]

in my experience 95% of the time when the battery light is on its an alternator failure,
usually the internal regulator fault.

 

[jhammel85]

I agree that this is most likely whats going on. You can take it off and run it over to a local car parts store like advance and have it tested.

 

[Warren 86 ranger]

I agree that this is most likely whats going on. You can take it off and run it over to a local car parts store like advance and have it tested.

welll how is it going out when the battery is always charged and i checked the voltage when running it is at 14.5 volts which of my knowledge is on the money

 

[Stxrangerbumper]

check your belt tenssion and belt not crack

 

[jhammel85]

welll how is it going out when the battery is always charged and i checked the voltage when running it is at 14.5 volts which of my knowledge is on the money

I'm just saying perhaps it's getting weak since it has to be reved up to make that light go away.

If the belts and external wiring checks out, I would just have it tested for peace of mind. Its easy enough to take out, you know?

 

[fomoco83]

another problem could be that 1 pin white wire, loose or corroded conection there will turn on the battery light, or it just could be a bad diode that is hard to diagnose unless you have proper test equipment

 

[kimcrwbr1]

The diode is like a check valve it only lets voltage flow in one direction. Take a ohm meter and isolate one side of the diode check for continuity in both directions switching the test leads around. Infinity in one direction or open and closed or high resistance in the other. When the voltage output from the alternator is less than the battery voltage the direction of current reverses turning on the light. That is why when you turn on the ignition the light stays on until the engine is started. DC current always flows from neg to pos.

 

[Spott]

Holy necro-post, batman!

Spott