lhgdale

Hello, I have a 92 LS 400 with 117,000 miles on it. The car starts up quickly and idles smooth. I did change the power steering pump a few months ago when I first purchased the car due to a leak.

While driving down the road and interstate my headlights will dim quickly and then go bright again (flicker). They do not do this constantly maybe every few minutes. I started noticing this 2 nights ago but it seems to be getting worse. I also noticed when I got to work the lights will dim at idle 600rpm and then get brighter when you step on the gas a little. The lights also flicker once when you step on the brake.

I am guessing it is the alternator but would like your opinions.

Thanks for the help!

LScowboyLS

alternator or battery going bad, or bad terminals ( + side is common problem and replaceable from any Toyota dealer for $14) or else trunk harness hinge wiring short issue (search this forum, VERY common problem!)

PS - a power steering leak will kill alternators commonly on this model!

lhgdale

Thanks for the info!

I did search but only found alot of issues with the lights dimming when pressing the brake. I found nothing about the lights flickering dim at highway speeds.

All other electrical items on the car work as they should. I was hoping I caught the power steering leak soon enough to save the alternator but I guess not. It was a heavy leak.

LScowboyLS

just put a voltmeter across the battery at idle, if you have 13.4 or more volts with lights on, you are fine, also test at 2500 rom, should be around 14V - if these two measurements are OK, then alternator is likely good, for now.

Yamae

Your symptom reminds me of the initial failing stage of slip rings at the alternator.

One idea to check this is to measure the voltage as LScowboyLS is suggesting.

The other idea is to check the condition of actual slip rings removing the cover of the rectifiers at the alternator. This is not very easy to see but most of the alternators that had leaked P/S oil have badly deteriorated slip rings. It seems to me that the P/S oil melts slip rings and those become very thin.

lhgdale

Thanks, I will test it. I'm sure it is the original alternator so I'm not gonna be upset having to get a new one. I was actually going to buy a new(remanufactureed) alternator when I purchased the power steering pump.

Legender

Your best bet is to remove that one and have it rebuilt and but it back on... That is what I do. We have a little shop here in Richardson that does starters and alternators. That's always worked for me.. I'm with the others and put my money on the alternator since the P/S pump was known to be leaking... but get the voltage readings first to help with the analysis...

Crybicki

Yep, the previous posters covered it. The power steering fluid leaking onto the alternator would kill it. As far as the headlights dimming on the highway, its more than likely your alternator failing when it feels like it , i.e. on the highway.

My alternator has just recently started going bad, and when I turn my headlights on, my idle drops down because of the power loss, and when i hit my window switches with the headlights on, the lights will dim. If this happens to you, alternator should be your solution.

Hope you get it taken care of!

lhgdale

Thanks for all the help! I'm calling around town today checking on prices for rebuild.

LScowboyLS

the starter motor is almost always fine, here is the real issue:

dc893

thats exactly what mine did when the alternator started to go bad. it didnt take long for it to be completely ruined either.


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lhgdale

That is good to hear, I plan on changing out the alternator on my off days ( Thurs and Fri). I hooked up a battery tender to the battery this morning when I got home from work. It stayed on for about 14 hours and still not fully charged.

I called a local shop today about rebuilding the alternator and they want almost as much as I can get one for at advance auto parts. Plus I have a 50 dollar gift card for advance so I'll just get it there.

Thanks again!

LScowboyLS

Advance sells a good one, I have it! (if it is still the same one they sold last year)

I decided to pay the cheap core charge and keep the very well made NipponDenso that came with the car, you might want to rebuild it later!

lhgdale

I will do the same, the core charge is only 24.00.

Legender

We don't have advance auto here... and I hate Autozone quality... so that's why I chose the rebuild route... O'Reilly's generally has better quality parts so I use them more when I don't order online from Sewell.