low voltage ~~~BUZZER~~~

(andrewjet) · (andrewjet) **Join Date: Jan 2003** 07-05-2008, 6:36 AM

89' Supra..For years now my low voltage BUZZER and idiot light has gone off at low idle. Idle is good at 700-800 rpm's. So I stuck some paper in the hole to quite it down. But lately It just seems to be getting louder. Voltage is around 12.5-13 volts..battery has never gotton low and has not started? What up? Anybody have this happen to them? Jet

(peter_c) · (peter_c) **Join Date: Sep 2001** 07-05-2008, 6:58 AM

It should be 13.7-14.3 volts at all times. You have a problem that may be just a power feed problem or could be an alternator issue. Start testing the system with a simple volt meter.

(onamission) · (onamission) **Join Date: May 2002** 07-06-2008, 8:10 AM

There should be 4 set pots on that same board, 1 for the fuel, oil press., water temp. and battery. Just tweak the battery one a little.

(mikeski) · (mikeski) **Join Date: Aug 2003** 07-06-2008, 12:13 PM

If Larr's solution does not work run larger wires to the main distribution system, you are getting too much voltage drop. Some early 2000's Nautiques had the same problem.

(Message edited by mikeski on July 06, 2008)

(wakemikey) · (wakemikey) **Join Date: Mar 2008** 07-07-2008, 8:31 AM

<<There should be 4 set pots on that same board>>

Can anyone please clarify what the heck this means? What is a set pot? Located where, on what board?

(Message edited by wakemikey on July 07, 2008)

(onamission) · (onamission) **Join Date: May 2002** 07-07-2008, 1:31 PM

Set pots are adjustable resistors that can be changed with a small screw driver they are soldiered on the circuit board that runs the warning lights and older Supra boats. It's under the dash and about 3" square.

(wakemikey) · (wakemikey) **Join Date: Mar 2008** 07-08-2008, 5:58 AM

Thanks Larry!!! I will try that ASAP. I was reading the manual for my 87 Supra SunSport and it says idle rpm should be 5-600!! That is just so low I can't even imagine it. I was at ~800 and sometimes low idle was a bit rough so I bumped it up to 900.

Still not smooth how I would like it. I'm thinking of changing serpintine belts thinking a new one will be tighter (I see belt dust) but I think it's a pretty old belt.

I also changed the battery to a nice new large marine batt and boy did that help.

UNfortunatly last time I was out my flywheel on my starter conked out! Sheesh! At least it's all little stuff. We will grease it and hope that does the trick as it's not really broken, just not catching.

(rodmcinnis) · (rodmcinnis) **Join Date: Sep 2002** 07-08-2008, 5:58 PM

I have the same issue on my SAN. The basic problem is that the alternator puts out very little current when the engine is at idle so if you are using a lot the voltage will drop.

If the buzzer is going to do you any good at all it needs to indicate the low voltage before it gets so low that you will be stranded.

In my situation the only time I have an issue is when I am running a lot of stuff: The stereo is going, three ballast pumps working away, maybe I left the blower on, and even worse if it is cold and I am running the heater.

At least my alarm just gives a short beep every ten seconds or so, easily ignored.

I recommend using a digital volt meter to see what the alarm is complaining about. If the voltage is 13 volts or more then I would adjust/repair the alarm. If the voltage really is low and there is a reason for the voltage to be low then I would just accept the fact that the alarm is doing what it is supposed to.

Rod