Ultramusique Posted September 26, 2006 Share Posted September 26, 2006 Hi! New to the forums. Just picked up a 1993 SC400 with 83,000 miles. Every 3rd or 4th time I start up and drive the car, when I turn my turn signal on the dash lights will flash and the radio cuts out for a second. Then when I shut off the car, the interior lights are real dim, and the auto-tilt doesn't retract, as if the battery were dead or something. If I turn the key to turn the car back on, nothing happens. But if I leave it turned, a second or two later everything comes back on full power and she starts right up. Then she'll drive fine with no problems for the next 3 or 4 times... What the heck? Could it be a bad battery? A bad ground? Any thoughts would be awesome!! :D Quote Link to comment Share on other sites More sharing options...
bubbasc400 Posted September 26, 2006 Share Posted September 26, 2006 I had the same problem about a month ago. I thought it was my battery and I replaced it, then the same thing happened about 2 days later. So I put it in the shop to get the alternator replaced and it wasn't the alternator. Come to find out that my power steering hose had a whole in it and the seal was busted also. The fluid was leaking on the alternator and it was causing it to short out. So you might want to have your alternator tested and check your power steering surroundings. Quote Link to comment Share on other sites More sharing options...
Ultramusique Posted September 26, 2006 Author Share Posted September 26, 2006 I had the same problem about a month ago. I thought it was my battery and I replaced it, then the same thing happened about 2 days later. So I put it in the shop to get the alternator replaced and it wasn't the alternator. Come to find out that my power steering hose had a whole in it and the seal was busted also. The fluid was leaking on the alternator and it was causing it to short out. So you might want to have your alternator tested and check your power steering surroundings. Awesome. Thank you!! I know the alternator has been replaced as was something related to the power steering... and possibly one or the other was not done correctly or is faulty. Quote Link to comment Share on other sites More sharing options...
jjgilham Posted September 29, 2006 Share Posted September 29, 2006 I had the similar problem with my 93 SC300 with about 90 K. Headlights dimming, stereo resetting occasionally, strange sequences of lights on the dash (ABS, battery etc.) while using the turn signal (particularly the left one). This problem was intermittent until the car ultimately died with a dead battery. Took it to Lexus dealer, they replaced the alternator and the symptoms improved but were still present. I took it back a month later and they told me that the alternator controller unit was bad. They said this part rarely fails and they don't routinely replace it when they do the alternator. They were decent and only charged me for the part as they felt they had not diagnosed the problem correctly initially. This solved the problem completely - however 1 year later the same symptoms are showing again. I'm very interested in what you find out - please post your results. I'll probably take it back to the shop so I'll post my results as well. I can't imagine what explains the controller unit (I can't remember what the part is called) could "fix" the problem but then fail again 1 year later. Could there be some other electrical fault (bad cable, bad grounding) that is causing the controller to malfunction or fail? Quote Link to comment Share on other sites More sharing options...
Ultramusique Posted September 29, 2006 Author Share Posted September 29, 2006 I had the similar problem with my 93 SC300 with about 90 K. Headlights dimming, stereo resetting occasionally, strange sequences of lights on the dash (ABS, battery etc.) while using the turn signal (particularly the left one). This problem was intermittent until the car ultimately died with a dead battery. Took it to Lexus dealer, they replaced the alternator and the symptoms improved but were still present. I took it back a month later and they told me that the alternator controller unit was bad. They said this part rarely fails and they don't routinely replace it when they do the alternator. They were decent and only charged me for the part as they felt they had not diagnosed the problem correctly initially. This solved the problem completely - however 1 year later the same symptoms are showing again. I'm very interested in what you find out - please post your results. I'll probably take it back to the shop so I'll post my results as well. I can't imagine what explains the controller unit (I can't remember what the part is called) could "fix" the problem but then fail again 1 year later. Could there be some other electrical fault (bad cable, bad grounding) that is causing the controller to malfunction or fail? I'm taking it to my mechanics next week and leaving it with them. They are pretty sure they are going to figure it out. I am trying to avoid taking it to the dealership! Quote Link to comment Share on other sites More sharing options...
mehullica Posted September 30, 2006 Share Posted September 30, 2006 Common for sc 300's to get high voltage drop on the ground side. Check the voltage drop, if high replace the ground cable as it gets comprimised from oil changes, the oil filter drips on the ground cable during removal and over time damages the cable. SC400's have weak grounds to begin with, and weak alternator output at low rpms, no oil damage to cable on a sc400, just poor grounds, and swapping over a pulley from an LX470 alternator to the sc400 alternator helps improve the charging at low rpm's Quote Link to comment Share on other sites More sharing options...
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