Battery Light Problem

[liljon]

Hey i just bought my msp about like a month ago. for some reason when i speed from time to time or like I'm smashing it my gauge cluster and headlights get really bright and my battery light turns on. and if i go into neutral and let the rpm drop it goes back to normal. but if i keep on going then my music stops working. anyone got any idea on whats wrong with my car? =[

 

[BOOSTR]

Never had this issue but I would start by checking the battery(load test it), tightening the cables and checking and tightening the alternator wiring. Sounds like you might have a few loose things since the music dies randomly as well. Strange one but probably an easy fix.

 

[Hans507]

im having the same issue but i have a voltage gauge and its never stable...at idle it drops to 13.0 and if i push it over 4k rmps the voltage spikes to 15.9 i have checked everything...nothing is loose....i think this is not as simple as you say BOOSTR...a dont have any DTC code but im gonna do a test i saw on the workshop manual...but i thing that maybe the alternator needs to be replaced

 

[liljon]

yea im bout to take my car to the dealership sometime this week to get it checked out. since i got my warranty still might as well take advantage of it. hopefully its just the alternator. people are either telling me between the alternator or the battery.

 

[orng1]

I think that battery is toast, might try checking the terminals as they may be dirty or corroded. The lights get bright as the voltage regulator is going crazy to keep your car running and as the RPM's go higher the voltage gets higher too.

 

[Hans507]

im going to try putting my alt in another car and see what happens....

 

[Hans507]

about the battery....im not sure cuz the car starts fine and the bat voltage is 12.5 but i havent done a load test yet

 

[Hans507]

i replaced the voltage regulator and it still going over 15.5v and the bat light comes on in the dash...whenever i go over 4k rpmsk....im really pissed

 

[Dpwhitehead1]

you could have a bad alt.. that's my guess. i've got one here at my house if you're interested.

tighten all the belts down well. check the battery terminals, make sure they're tight..

 

[Bigway]

I don't think it's either one the pcm controlls the charge. Maybe you have a bad ground somewhere.

 

[Hans507]

you could have a bad alt.. that's my guess. i've got one here at my house if you're interested.

tighten all the belts down well. check the battery terminals, make sure they're tight..

how many miles does the alternator have???

I don't think it's either one the pcm controls the charge. Maybe you have a bad ground somewhere.

well and how could i know if i have a bad ground

 

[Dpwhitehead1]

how many miles does the alternator have???



well and how could i know if i have a bad ground

pfsst. idk. maybe 30-40k?

 

[Wagonbacker9]

I'd say the voltage regulator is dying.... and seeing as its most likely part of your alt... probably just replace the whole thing.

 

[orng1]

i replaced the voltage regulator and it still going over 15.5v and the bat light comes on in the dash...whenever i go over 4k rpmsk....im really pissed

I'd say the voltage regulator is dying.... and seeing as its most likely part of your alt... probably just replace the whole thing.

He alredy did the regulator and he checked the battery. I'd do both at the same time. I can get both an alternator and a battery for under $100 near my house. Of course both rebuilds but with warranty.

 

[greasemonkey524]

I thought the voltage regulator was part of the ECM?

 

[Dpwhitehead1]

I thought the voltage regulator was part of the ECM?

nah.

 

[Wagonbacker9]

He alredy did the regulator and he checked the battery. I'd do both at the same time. I can get both an alternator and a battery for under $100 near my house. Of course both rebuilds but with warranty.

sonnova, missed that. my bad. thats very strange, because the voltage reg should preclude the alt from exceeding somewhere in the range (don't know exactly what it is) of 14.4 volts.

I thought the voltage regulator was part of the ECM?

^

nah.

 

[orng1]

It should unless there is a problem, if you disconect the battery while idling and test it you will see it shot way over 14.4 to like 15.3 at idle.

 

[Hans507]

im just thinking on replacing the whole alt bat combo

 

[Bigway]

the pcm controls the what the alt is putting out. their is two wires coming from it one is Lg/w stripe and the other is W/L stripe. I think that the W/L tells the pcm what is going on with the alt and changes the charge rate. I would start there also the driver side strut tower their is a clip there with some ground wires I have found some corrosion under it their that first.