As the subject says, I have an '84 Supra (5M-GE) and the Alternator warning light and the Brake warning light are almost always on. They come on together and go off together. Also, the alternator voltage jumps around occasionally, sometimes jumping up to around 18 volts, but most of the time it sits right where I expect it to be.
I'm assuming that these two items are connected, but wanting to check and see if I'm right before taking it off and getting it replaced. Thing is, the lights are on even if the voltage isn't fluctuating, so that's why I'm a little uncertain. Ideas?
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Re: '84 Supra - Alt & Brake warning lights always on
It's possible that the voltage regulator is shot. I don't know whether the regulator is integrated into the alternator on your car, but a Toyota parts counter (call your dealership) can tell you, if you ask them for a new voltage regulator. They'll tell you if it's available separately or if it is part of the alternator.
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the alt glows, when the charge system fails.
belt feel off? or engine RPM way below 800rpm hot?
or bad, battery, wiring or alt.,
the brake lamp comes on for every key on, for self test.
and at each engine stall. this is NORMAL.
the brake lamp warning glows usually for 4 reaons.
1: hand brake stuck on, or its switch.
2: low brake fuild.
3: front or rear brakes have failed (the balance switch)
4: ABS if fitted, is having , well Fits.
You mentioned "alternator warning light" if that alt, battery light does not come on when the key is turned to the "on, acc." position the light bulb is bad or the traces leading to that light bulb on the back of the instrument cluster has a break in it. I know this sounds crazy but if that light bulb does not light it does not complete the circuit for the alt to charge!
The alternator is bad, this is the way foriegn car makers do things, when the alternator is bad or going bad and if it has a bad diode the dash lights will light up like the batt and brake and sometimes even other waring lights, replace the alternator and the problem will be sloved. good day,
The alternator light and brake light are hooked together. The brake light can come on by itself, but if the alternator light comes on the brake light always comes on this is normal. But it isn't normal for them to be on. It sounds like you have a bad voltage regulator. I
With the regulator built into the alternator these days, there is just power, ground, and the warning light wire.
The power is always large and usually is held down with a nut.
The ground is usually smaller, and held down with a nut.
You an tell both power and ground with a test light.
The warning light wire is usually a push on connector.
But this is mostly generic info, and not Jaguar specific.
If you have changed the alternator and regulator, about all that could be left would either be a short circuit that is draining current away, or a bad ignition warning light bulb. That is because the power to energize the field of the alternator, comes through this dash bulb.
hi check the charging rate at your battery terminals under load [lights on heater on wipers etc] if drops below 13v with these on its to low if you have checked the output of the alternator at the alternator it should read not under 14v and not over 14.5v i think you will find the regulator is in the alternator or on the outside of it but if your readings at the battery are correct test your battery with a voltdrop test or if the batterys flat take the tops off get someone to keep the key in start position and see if the cells are bubbling it only takes one is so replace the battery yates210456
You said you replaced the plugs - did you use the toyota platinum plugs? I found out the hard way that even the platinum plugs from bosch or any other kind of platinum plug just doesn't work right. Yes, they are more expensive from toyota, but they can make a difference in the way the engine runs.