battery warning light / tail lamp failure warning light

MattJ · 02-05-2006, 12:22 AM

hello everyone!

I'm new to the ownership of the mystical Toyota Supra and a problem has reared its head already! lol

I have got an '87 supra with the 7M-GE engine.

Last night the battery light came on while driving and the 'volt' gauge now sits at about 10-11v. Also the 'rear light warning' light has come on the dash, are they related? I have had the rear lights checked out and all the lights work?

I assume the alternator might have decided to pack up but the problem just suddenly happened! One minute showing a healthy 14v on the gauge then down to 10v!

Is this a known problem at all? Like some dodgy earth or something?

Alternator looks easy to change but i dont want to unless i have to!

Thanks for any help

MattJ

djalkyd · 02-05-2006, 12:49 AM

thats a good question because my brake light lamp is on also. i was thinking it was fluid level or something but i added fluid but the light stays on. i just deal with it for now but it would be cool to have that thing off.

MattJ · 02-05-2006, 12:51 AM

Yeah it is a pain. only had the car 2 days!

dcrusupra · 02-05-2006, 02:30 AM

Check the brake bulbs. If one is burned out the light usually goes on. I have no clue about the battery tho. Sorry.

Burn N' Up · 02-05-2006, 03:29 AM

Start trouble shooting. Get a multimeter and check the voltage in the battery. Then check the voltage and amperage coming off the alternator when the car is running. When running you should see 10A or less between the Alternator and Battery and 13.9-15.1v between the alternator and ground. If not get the battery tested at Autozone or Kragen or whatever and if the battery checks out, check all your fuses and start thinking about replacing the alternator or IC regulator. There is another test you can do to make sure its the alternator and not the IC regulator but you'd need a 30amp ammeter to do it. If everything checks out and its not the alternator or battery then its could be the gauge.

Hope this helps.

MattJ · 02-06-2006, 07:22 PM

Thanks for the reply's

Turned out to be the alternator in the end

Matt

02-05-2006, 12:22 AM	#1
MattJ Stock Join Date: Feb 2006 Location: Kent, UK Posts: 5	battery warning light / tail lamp failure warning light hello everyone! I'm new to the ownership of the mystical Toyota Supra and a problem has reared its head already! lol I have got an '87 supra with the 7M-GE engine. Last night the battery light came on while driving and the 'volt' gauge now sits at about 10-11v. Also the 'rear light warning' light has come on the dash, are they related? I have had the rear lights checked out and all the lights work? I assume the alternator might have decided to pack up but the problem just suddenly happened! One minute showing a healthy 14v on the gauge then down to 10v! Is this a known problem at all? Like some dodgy earth or something? Alternator looks easy to change but i dont want to unless i have to! Thanks for any help MattJ

02-05-2006, 02:30 AM	#4
dcrusupra 500whp yet? Join Date: Aug 2005 Location: Plantation, Fl. Posts: 1,052	Check the brake bulbs. If one is burned out the light usually goes on. I have no clue about the battery tho. Sorry. __________________ New Rebuild My CarDomain

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02-05-2006, 12:49 AM	#2
djalkyd 3" Exhaust Join Date: Jan 2006 Location: sacramento ca. Posts: 55	thats a good question because my brake light lamp is on also. i was thinking it was fluid level or something but i added fluid but the light stays on. i just deal with it for now but it would be cool to have that thing off.

02-05-2006, 12:51 AM	#3
MattJ Stock Join Date: Feb 2006 Location: Kent, UK Posts: 5	Yeah it is a pain. only had the car 2 days!

02-05-2006, 03:29 AM	#5
Burn N' Up 3" Exhaust Join Date: Sep 2005 Posts: 238	Start trouble shooting. Get a multimeter and check the voltage in the battery. Then check the voltage and amperage coming off the alternator when the car is running. When running you should see 10A or less between the Alternator and Battery and 13.9-15.1v between the alternator and ground. If not get the battery tested at Autozone or Kragen or whatever and if the battery checks out, check all your fuses and start thinking about replacing the alternator or IC regulator. There is another test you can do to make sure its the alternator and not the IC regulator but you'd need a 30amp ammeter to do it. If everything checks out and its not the alternator or battery then its could be the gauge. Hope this helps.

02-06-2006, 07:22 PM	#6
MattJ Stock Join Date: Feb 2006 Location: Kent, UK Posts: 5	Thanks for the reply's Turned out to be the alternator in the end Matt