SlowRider1

hi, i hope someone can help me here because i am at a complete loss as to what is going on with my car 1999 ES300 150k miles.

for the past 2 weeks i had this problem:
The car starts fine and drives good for about 10-15minutes. Then the BATTERY LIGHT comes on and at the same instant lights (headlights and center console clock) get brighter, fan blows faster. after a few seconds the BATTERY LIGHT goes off and immediately AIR BAG light comes on. at the same time lights and fan go back to normal. then this whole thing repeats every 2-3 minutes until the scary thing happens!! the entire dashboard lights up (VSC OFF, CHECK ENGINE, AIR BAG, every possible warning light comes on) and the speedometer needle drops to 0 even though the car is driving fine. after a few seconds the speedometer comes back to life and while driving VSC OFF and CHECK ENGINE and every other warning light except for AIR BAG go out. the AIR BAG light stays on for a while and then also goes out when BATTERY LIGHT comes back on. then the whole thing repeats itself: lights get brighter, fan blows harder until BATTERY LIGHT is replaced by AIRBAG LIGHT

known issues:
1.center console clock is so dim its barely visible and it was like that for 2 years now. but when the BATTERY LIGHT comes on it becomes bright as it should be.
2. Headlights and Domelights are constantly flickering when the engine is running.
3. valve cover gasket is bad, so there is some oil on the block, but alternator is clean.

the alternator was rebuilt by a local shop last summer but works. I tested it by disconnecting the (+) terminal from battery after starting up the car and it was running for 10min until i shut it off. the battery is old, but not sure if its dead yet. voltmeter reads 12.36V on battery (car not running), same from (+)alternator to (-)battery. I checked the ground connections on battery, they all seem to be fine. the alternator connector has 1 wire that is a bit worn but since the car runs fine with battery disconnected i dont' think its a problem. i also checked continuity of (+)alternator to (+)battery, no problems there.

any suggestions? please someone point me in some direction. my main concern is that these lights on dashboard come on intermittently, I hope my ECU is not acting up.

GEORGE_JET

I believe that these alternators have a internal regulator,, so the ECU would not cause the voltage to vary. I strongly recomend not running the car with the battery disconnected. That was a good check in the old days, but it can hurt the electronics in a modern car.

You mention one wire is worn on the alternator, which one?

Also, measure voltage drops from the battery to the alternator. Start the car, and then turn everything on (high beams, ac, high fan). Then measure from the alternator output, to the battery, you should see less than 0.5 volts ( the less the better). Then do the same from the battery grd, to the engine block, and then the battery grd to the alternator case.

If all that looks good, then start measuring the voltages at the fuses, make sure that there is a load, because the DVM has far too high of a input impedance to tell you if there is a poor connection.

ASG14

iTrader: (1)

Measure the voltage with the car running. I ended up replacing my Alt after my battery died. Couldn't figure out what happened. Had a weird feeling and checked the Voltage while car was running, and it was around 16V being pumped into the car. Reverse fail for my Alternator.

GEORGE_JET

I would still recommend checking the voltage drops. It is very possible that the alternator died because you disconnected the battery. The original problem may still be there. The poor connection could be the cause of your problems.

SlowRider1

thank you all for your input. I will post back soon.
I was thinking to tighten the belt on ALT, or replace it altogether as trial/error attempt.

SlowRider1

I went to local junk yard and got a working OEM alternator for 35. just wanted to check if it might solve the problem and it did.

the only issue which i still have (which annoys me very much) is pulsating/flickering lights and dim clock in center console.

I saw one forum user suggest changing the fuses, but if they are good does it really make sense to change them?

rvajw

I experienced the problem with my lights flickering in the dash, interior lights, and head lights. Took the alternator (100 amp) off and delivered it to the alternator & starter specialist for a rebuild. After testing, it was taken apart and found that the brushes & and voltage regulator were in excellent condition and the real problem was the Rectifier (which had burn marks). The Rectifier was replaced with a heavy duty one, and the problem solved. The shop gave me a one year warranty & the total cost of repair was $90 dollars. no problem in four months and still going.

polatok

alternator for $35?!?! where in ny are you man!? i was looking for the driver side taillight and i got $80+ quoted on the 4 junk yards ive been to so far!

yeskay

rvajw:

can you provide more details. rectifier converts ac to dc. after putting the heavy duty ( ?) rectifier did they measure the amp. is it a oem alternator

Hayk

iTrader: (1)

I was going to suggest a bad/loose body ground wire, but it seems like you have found the real problem.

rvajw

MrBobby, don't know if the amps was measured by the repair person and the Alt. is OEM. The vehicle has a 130,000 miles on it and I drove approximately 500 miles this weekend (65 percent @ night) and no problems noticed. I do have an built in A/C power plug in the car and is used often to power computers so I don't know if this caused the problems with the Rectifier. I do have 8 months left with the warranty, so if the problem comes back I will take the alternator in for repair and post the findings.