battery light on, off


Asked by Jun 14, 2014 at 08:35 PM about the 2002 Toyota Tacoma 2 Dr STD 4WD Standard Cab LB

Question type: Maintenance & Repair

I took my Tacoma 2002 to the shop because the battery light came on several times; the service guy tested the battery and the alternator and both checked OK
What else can cause the light to turn on?

15 Answers


Loose/dirty battery connections will cause this. Also check the negative battery connections on the frame and motor. Loose/slipping alternator belt will also cause this.

7 of 7 people found this helpful.

dandyoun has the best DYI for you to do. (How tos are elsewhere in the forum). Then if you do need to have it worked on. I'd take it somewhere else. No certified mechanic would have let you drive off without checking those other "normal" possibilities. Your guy was ineffective at best.


dandyoun, I have checked the terminals and connections. Everything is tight and clean. The dealer service receipt mentions they checked the belt and everything OK. Is it possible that Emissions problems could cause service lights to come on? Thanks for your answers, guys.

3 of 3 people found this helpful.

Is it your battery light or check engine light(service engine)? If check engine light then have the codes read. Auto zone will do this for free. Post codes back on here and we can narrow down the issues you are having. Check engine light typically is an emissions issue. Need to have codes read. Serious damage can be caused to cat converter in some situations.

2 of 2 people found this helpful.

No, it is the battery light. The car starts OK, then the light comes on and after driving for a while goes out. I do not have Autozone in town, can I drive safely to the next town, about 20/30 miles?

5 of 5 people found this helpful.

Ok battery lights are typically turned on due to one or more of the following. Loose connections, dirty connections, worn out connectors, dirty/loose frame /motor negative battery connections, loose alternator belt, weak/bad battery and/or weak/bad alternator. I feel you will find your solution in one of these items.

3 of 3 people found this helpful.

With it coming on then going out I would check alternator belt tension first.

1 of 1 people found this helpful.

So I am dealing with this problem now. My 2001 Tacoma has ran great but for a while I could hear a belt slip but didn't cause any problems Then this Thanksgiving weekend the light was on and the battery was dying. Radio, dash, and heater fan all stopped, then the truck stopped cuz there was no more battery to power the fuel injection. So I bought a new battery to keep from being toed. Worked till I got where I was going. We took the battery out charged both (old and new battery). Cleaned all the terminals cuz I have a corrosion problem. Got home and took it to the shop. They changed the bets and connections and what not. Sent it home. Worked for a day. The following day the starter seized up. Took it back, they replaced the starter. And now today the battery light is back. Off and on. Idk what else to do.

11 of 11 people found this helpful.

Problem solved, Finally my car started to slow down and stopped (thank God!) when arriving at my house, It was a bad alternator. I had to replace both to the tune of $8oo+.

1 of 1 people found this helpful.

Tessa2002 Thanks for the update; good to know you're on the road .


$800 to replace the bad alternator? $800? Holy Chit my man. It's a Toyota not a Maserati

1 of 1 people found this helpful.

WOW! I'm researching for a friend and she is going to buy a $150 alternator and a 12 pack of beer for me to replace it. Youtube video shows only 2 bolts on alternator, 1 bolt on tensioner, 1 bolt on electrical wire to alternator, and 1 bolt for negative terminal on battery. $800 was pricey!

1 of 1 people found this helpful.

Hope that beer is worth the labor, on my taco I am going to have to go through the wheel well to replace my alternator, 2010 and up were bad designs by toyota

I replaced my alternator and battery at 59,000 miles on my 14 tacoma. Should not have happened! Voltage regulator was bad. Now, 12,000 miles later my battery light starts flickering and staying on intermittently. Trying to read up on this. This is BS. Last toyota I ever buy. Radiator leaked the day I bought, leaf springs had to be replaced inntje first few months. My stereo went through a period of just powering off for periods of time. Its a 20 gallon tank but you can barely get past about 16 gallo s because it wont vent and sprays fuel everywhere unless you find a pump that pumps very slowly for the blast 4ish gallons. I'm sick of this damned truck.

Hey guys, New here. I have a 1997 Tacoma V6, since last week my battery light started to come on and go off at random times. hooked up a volt meter to the battery and it read 14.19V while running and then luckily the battery light came on again and noticed the voltage dropped from 14.19V to 11.9V all within 5 minuted or so. I killed the truck and started it back after an hour and the light never came back on and volt meter read 13.6V under load and without load. I know the problem will come back at some time, but not sure what to replace. Truck has over 300,000 miles on it. Alternator never been replaced, so I am leaning toward the alternator going bad, but not sure, Any Ideas?

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