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mike switzer
mike switzer,
Category: Mitsubishi
Satisfied Customers: 712
Experience:  lead diagnostic tech at Aamco
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I put a new alternator in my 2003 eclipse, brakes, calibers,

Customer Question

HELLO, I put a new alternator in my 2003 eclipse, brakes, calibers, battery, etc. My battery light and brake light continues to stay on. What else could be the problem.
JA: Have you tested the battery? Have you tried testing the alternator?
Customer: Yes, both are good.
JA: Are you fixing your Eclipse yourself? What have you tried so far?
Customer: no, wish I could. The mechanic I used cant seem to understand why the brake and battery continues to stay on. could it be an electrical problem
JA: Anything else you want the mechanic to know before I connect you?
Customer: No, I just need to make sure my car will not give out on me while I have my kids in the car, especially in the cold weather. Oh I do know that my speedometer and odometer doesn't work anymore. the only thing that works on the dashboard is the gas level and the rpms.
Submitted: 9 months ago.
Category: Mitsubishi
Expert:  mike switzer replied 9 months ago.

for the brake light looking at your master cylinder is there a two wire plug on the reservoir? and for the battery light after alternator replacement or before did you measure charging voltage?

Customer: replied 9 months ago.
Alternator is reading 14.8. When the alternator is disconnected all the lights go out but when connected the battery light and brake light comes on. it's not the master cylinder. Also I forgot to mention that air flow or map sensor, when disconnected, the car runs smooth but when connected it always sounds like the engine is reving up. Please advise.
Expert:  mike switzer replied 9 months ago.

the maf sensor is giving a bad signal to the ecm and causing it to idle up. the voltage is a bit high and high voltage can cause a light aswell. do the lights go out when the maf and map are unplugged out only the alt?

Customer: replied 9 months ago.
just when the Alternator is unplugged out only. The lights stays on when the Maf and map are unplugged.
Expert:  mike switzer replied 9 months ago.

was the brake and battery light on before replacing the alternator?

Customer: replied 9 months ago.
Expert:  mike switzer replied 9 months ago.

what do you disconnect on the alt? the main battery or the plug? also does it idle down when you do this or only wen the maf sensor is u plugged.. also do the maf and map have to be unplugged togetheror just one?

Customer: replied 9 months ago.
The main hot wire to the alt when unplug the light stays on still... 900 rpm when the maf is unplugged
Expert:  mike switzer replied 9 months ago.

so you will want to replace the maf and it sounds like the alternators internal regulator is bad. im guessing since you just replaced it you should be able to exchange it.

Customer: replied 9 months ago.
Ok. I mistyped something. I meant to say when the main wire is still plugged in the alt and the focus regulator is unplugged the battery light and brake lights are still on and the alt is still charging
Expert:  mike switzer replied 9 months ago.

that still indicates a failed alternator regulator with the alt unplugged it should not charge since the regulator wont cite it.