i have a 99 es300 and my lights are pulsing just the slightest bit.
i just replaced the alternator that also has the voltage regulator attached.
the battery is fine and i am going to replace the alternator belt.

i can be on the gas or stopped and the pulsing light still occurs.


what can be the problem??
can it be a bad ground? this happens 100% of the time to the car

 

bueller?

 

my dads 95 camry would do that too even though the battery and alternator were good

 

it still drives me nuts

 

It could be a bad ground or a loose or corroded connection. If you disconnect the electrical connector from the harness, try spraying it with wd-40 to displace any of the water that may be intermittently disrupting the flow of electricity. If that doesn't work, check with a place that specializes in auto electrical work.

Something similar happened on my old Maxima and it kept happening even after it was "fixed." The shop had to replace a length of the wire supplying the positive lead to the light and splice in new connectors. The situation was analagous to that of a set of old headphones where the sound cuts in and out in one of the earbuds because the wiring is old and the resistance along the length of the wire is no longer uniform.

 

i will check these connections again, grounds can be tricky

 

i checked all grounds and all are solid and the wires are fine. i also checked all fuses in the engine bay

 

Definately a ground issue...get it looked at!

 

i may eventually do that. i think i will scour the rest of the car for grounds and then get it done.

it is puzzling

 

update............................




i started to pull fuses in the engine compartment. i started to pull a few at a time. keeping the ones that are important to keeping the motor running, i pulled things like the radio, heater etc.

then i finally got to the a/f htr fuse.

this is the air fuel ration sensor
once i pulled it the lights were normal and i had no pulsing, i reinstalled it and it pulsed.

i tried it a few times and this seems like the culprit.

any help with this discovery would be helpful

 

spray the socket with contact cleaner and try a new fuse. Electrical systems can get funky off of one wierd fuse, even if that fuse still works.

 

even if i tried a diff. fuse?

 

but i will try contact cleaner tomorrow

 

ok tonight i unplugged both o2 sensors, one at a time, and still had the pulsing.

i then unplugged one sensor at a time that i could reach, and still nothing.
i unplugged the harness on the alternator and then the tps, and still nothing.


i unplugged the fans and prob a total of 10 -15 sensors w/o any luck.



i then looked at the fuses/relays connected to the battery, i located a a/f htr relay. i unplugged it and the pulsing stopped.

so i am getting somewhere. so i wrote down the info on the relay and found one on fleabay. i offered $6 from the $10 buyit now price plus shipping of $5 so hopefully it will cost me $11



does this sound like a relay could be bad?? esp after i disconnected these sensors?

 

 

at least this is a pretty cheap option compared to replacing sensors

 

well it's not the relay. i tried one from the wifes' 4runner