nicks88

Hey all, I was curious to know if anyone has any idea if a stronger output alternator off of another Toyota/Lexus model with fit a 1996 ES300? I have replaced mine with the same alternator, however the same "issues" are still there ie. When wipers, lights, radio etc are all on, and car is stopped at idle, the wipers get slow, and the lights dim, and you can see the cruise control light on the dash fade in and out when the turn signal is on as well. Thank you in advance!

randal

Maybe the issue is not the alternator output at all. Internal resistance of wires and connections will cause excessive voltage drop(IR) and produce the very symptoms that you describe. Have you inspected (and/or cleaned) the alternator wiring and battery connections carefully?

nicks88

I have cleaned and tightened the cables and wires very well. Would a loose ground cause this? If so, where are all the grounds?

randal

Yes, a bad ground could cause voltage drop issues. The main grounding paths for the alternator are through the mounting bolts to the engine block and then from the negative(-) battery cable from the block to the battery. You can measure the charge voltage directly at the battery and again at the alternator output to determine if there is a bad connection. You should not see more than several tenths of a volt drop, if that.

Now, please understand that most all vehicles will NOT charge at idle when all accessories are on. The owner's manual will (usually) state this fact. If you have a lot of power-hungry accessories on (the most hungry being seat heaters, rear defroster, brake lights) then the only way to bring the charging voltage up might be to increase the engine idle. And it really does not take much. Several hundred RPMs can make a huge difference.