2000 Tacoma battery light issue
02-26-2019, 04:31 AM
#1
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Thread Starter
2000 Tacoma battery light issue
I have a 2000 Tacoma 3.4 engine and the battery light comes on sometimes. I checked the voltage and it was 13.2 truck off 16.3 truck started. Way too high I have replaced the battery and alternator and checked /cleaned all grounds and terminals. The light is still coming on somtimes so I put a voltmeter on the cig lighter to check while running. The voltage is 15.3 when light is off then if I take off from a stop quickly the batt light comes on and the voltage drops to 14.2. WTF! The batt light is only coming on when the voltage is correct. Why is my voltage too high. Any ideas?
02-26-2019, 02:45 PM
#2
Registered User
Are there upgraded accessories running?
I would think the new alt or new diodes would have solved the problem but it doesnt look like...was it a reman'd unit?
Loose alt pulley maybe?
I would think the new alt or new diodes would have solved the problem but it doesnt look like...was it a reman'd unit?
Loose alt pulley maybe?
02-26-2019, 06:51 PM
#3
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Thread Starter
yeah right. I don’t have any accessories on the truck. The alternator was a remanned unit from O’Reillys. I’m stumped. Why would it be putting out more volts than normal. The voltage regulator is on the back of the alternator. Weird.
02-27-2019, 11:15 AM
#4
Registered User
I had to replace my Original Alternator in my 99' last year as all the lights on the dash came on one day when I started it, ABS, Battery and i think airbag, ect. lite up, I was running 18V while running at 1500rpm, and 15-16V consistently 900-3000rpms with all lights, stereo, and fans on to limp home on 1 hour drive, changed the Alt and battery for a new premium from Carquest and all was good. There is a difference in the Amp output on a Canadian vs US for cold climate but that shouldn't make any difference, so I would opt for an exchange Alt ASAP, reman'd duds is a good possibility.
02-27-2019, 06:24 PM
#5
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Thread Starter
I figured it out. The plug on the back of the alternator had a wire that was really corroded. I stripped it till i got to bare wire and soldered a new piece of wire in a it’s rocking again.
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old87yota (02-27-2019)
02-27-2019, 10:32 PM
#6
Registered User
All right 
Makes me wonder if the old alternator would still work after all...
Unless we're talking about the 'new' one with corrosion on it. In which case, I'd get back money paid for it.
Good to hear its fixed.
Makes me wonder if the old alternator would still work after all...
Unless we're talking about the 'new' one with corrosion on it. In which case, I'd get back money paid for it.
Good to hear its fixed.
03-02-2019, 05:05 AM
#7
Registered User
Thread Starter
I think the old alternator was probably ok. But it was the original one so. I’m ok with the new one. What’s the chance an 18 year old alternator would last much more anyway. The plug on the car side was the corroded one.
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11-17-2019, 01:00 PM
#8
My alternator made it about 20yrs before the brushes wore down and by the time the battery light was staying on, brush arcing had damaged one of the slip rings.
My new alt, battery worked fine for months but now I have similar symptoms to yours. My voltage is OK, but the battery light flickers on and off, and the starter doesn't always kick over. You can bet I'll be looking at all the connections closely.
How/where is the block grounded to the chassis? I see the large batt negative cable bolts to the block under the oil filter, but I don't see any kind of block-to-chassis ground strap, just the 4" wire off the battery terminal. Other vehicles have ground straps across the motor mounts.
My new alt, battery worked fine for months but now I have similar symptoms to yours. My voltage is OK, but the battery light flickers on and off, and the starter doesn't always kick over. You can bet I'll be looking at all the connections closely.
How/where is the block grounded to the chassis? I see the large batt negative cable bolts to the block under the oil filter, but I don't see any kind of block-to-chassis ground strap, just the 4" wire off the battery terminal. Other vehicles have ground straps across the motor mounts.
Last edited by tns1; 11-17-2019 at 04:09 PM.
11-17-2019, 07:22 PM
#9
Registered User
How/where is the block grounded to the chassis? I see the large batt negative cable bolts to the block under the oil filter, but I don't see any kind of block-to-chassis ground strap, just the 4" wire off the battery terminal. Other vehicles have ground straps across the motor mounts.
it should be on the backside of the intake to the firewall.
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