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battery light on dash wont go out

 
hayabusa1--93lx ssp
New User
Posts: 24
Joined: 10/11
Posted: 10/03/11 05:51 PM

i have a 93lx former texas high way patrol mustang & my battery light wont go off i know that my optima red battery is a few years old but even when i charge it up yhe bsttery light stays on seems like i remember there being a blue wire being near  the battery that when i pulled the motor & reinstaled it was burnt or broken and when replaced my light went off & now after getting it out of the shop the wire was fused back together & i have it on the positive terminal of my solenoid but the battery light stays on can anyone give some resolution to this problem  

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waynep7122
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Posts: 194
Joined: 02/10
Posted: 10/03/11 06:39 PM

how about narrowing down the year...

The Ford Mustang SSP was a lightweight police car package based on the Ford Mustang produced between 1982-1993. The car was meant to provide a speedier option for police departments in lieu of other full sized (and heavier) sedans on the market at the time. The SSP abbreviation means Special Service Package, a special Foxbody Mustang trim made exclusively for law enforcement use. One of the taglines used by Ford to help sell this car was This Ford chases Porsches for a living

there are slight variations in the alternator output wiring....  several possible alternators.


do you have a test light...    do you have battery power on the back of the alternator output post???

there is a fusible link between the alternator and the starter solenoid ...... those can burn when stuff happens...

i drop by here a few times a day... try to post a year.. so i can get you the exact info you need... other than just generic..


edit. additional....

there should be at least one wire between the alternator output and the starter solenoid...

there might be one or two wires from the car to the voltage regulator connections...

it really depends on which alternator and what year....

you can take pictures and post them to photobucket... then post the 4th link down here .. that may make it a LOT easier to help you...


if the alternator output wire comes off.. and the alternator is charging at the time.. it will burn the alternator out...   the voltage goes up above the diodes rated voltage and they short or open...  

did all the ground wires get hooked up properly between the battery negative  and the engine..   bat neg and the body.. engine block and the firewall.????

if any of these are not properly installed you will have serious problems..  

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waynep7122
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Posts: 194
Joined: 02/10
Posted: 10/04/11 07:18 AM

i have an under 5 minute test... that will narrow down the problems...  this really does work.....


take a digital volt meter...  they start at 7 bucks and you don't need to spend more than 25 for one...


set the digital volt meter  to 20 volts DC scale...


start the engine.. turn on the headlights...


1.  measure from the positive battery post to the negative battery post...    14.1 to 14.8 volts is expected...


2.  measure from the Negative battery post to the engine block.. ...........   0.04 volts is expected


3.  measure from the Negative battery post to the body of the car...          0.02 volts is expected..


4.  measure from the Engine block to the body of the car..............            0.02 volts is expected..


if you get 0.00 on tests 2, 3, 4... change the meter setting to 2 volts DC scale and retest 2, 3, 4..

please post your readings.. by number..

this is the first test and it finds the biggest problems up front..   the car has to pass these readings or you cannot go farther...

it took me longer to type this than it will for you to test the car.

normal charging voltage is 14.1 to 14.8 volts... if you don't get that... there is a problem..

tests 2, 3, 4 show that the individual parts are properly grounded.. so there will be enough electrons when you need to operate something...     voltage readings over 0.04 or 0.02 volts show that there is a ground problem..

post your results...  

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9Sec93LX
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Posts: 6
Joined: 01/11
Posted: 10/09/11 06:02 AM

Start the motor up and let it idle. Disconnect the negative battery cable while the car is running. If it stalls the alternator is bad.  

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waynep7122
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Posts: 194
Joined: 02/10
Posted: 10/09/11 11:49 AM

Icon Quote9Sec93LX:
Start the motor up and let it idle. Disconnect the negative battery cable while the car is running. If it stalls the alternator is bad.

THAT IS THE WORST thing to do to a car...

you will usually Damage the alternator diodes pulling a cable off..  sometimes burning the alternator out instantly..

sometimes on cars.. taking out the ECM and hundreds or thousands of dollars of electronics...



when the alternator is charging..  its putting out electrons...  forcing them into the battery..   when you pull the battery cable off...  the electrons don't have anywhere to go...  so they build up as the alternator is still charging for that split second before the voltage regulator can reduce the output voltage...

the diodes in the alternators are usually rated at 25 amps at 100 volts PIV...   if you exceed the 25 amps flow you can damage them from over heating..   if you exceed the voltage..  you fry the diode.. either it opens or it shorts..  sometimes only part way.. so you get reduced voltage through the diode.. or no voltage through...

the instant you pull the cable..  the voltage can go well over 100 volts for that split second..  this is enough to damage many electronic systems in the car.. like the ECM and the car stereo.. and the stereo amp that all of you have installed..

would you plug your 12 volt device into the house outlet at 120 volts????  directly.. whats going to happen...

the term letting the smoke out of the wires comes to mind..

oh... dirty battery cables.. loose grounds.. dirty grounds.. dirty or loose connections at the starter relay..  can do the same damage to the alternator and other systems..

the test i posted above.   takes 2 minutes to do.. will find almost any hidden problem..  this is 2011.. not 1960..

the pull the cable test was promoted by UNKNOWING mechanics who wanted to change the alternator.. as they knew they were going to damage it.. as they wanted the job to change it..   yes.. there actually were and still are mechanics who will damage things to  get the job to fix them..  

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hayabusa1--93lx ssp
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Posts: 24
Joined: 10/11
Posted: 10/12/11 08:08 PM

hadnt gotten around to the car yet but a put an after market solenoid switch on it & theres a post other than the one for the starter is there supposed to be any wire connected to that post ... it's smaller in diameter than the one for the starter & it has a neg sign on i ...and the car is a 93 lx  

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waynep7122
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Posts: 194
Joined: 02/10
Posted: 10/12/11 09:44 PM

do you have a cell phone camera??? a digital camera of some kind.. you can take photos.. post them to photobucket..

then click on the 4th link down.. it will copy to your clip board.. you can then paste that link here and we will see what you are talking about..

you can also.. draw on the photo digitally before you post it to photobucket..

this is what the starter relay normally looks like...

in this image.. you will see an S next to the small stud on the left.... and a capital I next to the small stud on the right..



S is for solenoid windings..    when you turn your key to the CRANKING position..  you send voltage from the ignition switch on the right side of the column.. to the neutral safety switch on the side of the transmission then up to the S terminal..

the S terminal is connected to the windings inside the starter relay...  the other end of the coil is connected to the rear mounting flange...  so its a complete circuit...


the I terminal...   that is an Ignition bypass terminal.. not used on every car..  

when used on cars with electronic ignition..  that sends a 12 volt signal ONLY when the starter solenoid is engaged..   on duraspark 2 cars.. it connects to the white wire on the module to retard the timing 10 degrees for easier starting..

on point type ignition cars...    it bypasses the ballast resistor... sending full battery voltage do the positive side of the coil to make it easier to start...    ( the resistor reduced voltage is really not enough to start an engine)

i have not looked to see how it is used on TFI equipped cars...  it might be used to signal the ECM that the starter is engaged...  

i am drawing a blank on what else could be there.. but its late...

hope this helps...


Please pay attention to the location of the S terminal..   its next to one of the mounting ears...   the I terminal IS NOT...  

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hayabusa1--93lx ssp
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Posts: 24
Joined: 10/11
Posted: 10/13/11 07:03 AM

yep thats the kind that i have bout to try to get up off my lazy behind & try to go figure things out in alittle bit  

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9Sec93LX
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Posts: 6
Joined: 01/11
Posted: 10/16/11 04:27 AM

I had a bad battery and no jumper cables on my '86 Mustang. So for one week (until payday), every morning I had to take the battery out of my truck, start the Stang. Then remove both cables (insulating the cables from touching the body) and switch the batteries back and forth. Did this for 5 straight days and didn't hurt a single thing on the car. Owned it 3 more years after that and never had any electrical problems WHATSOEVER.  

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waynep7122
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Posts: 194
Joined: 02/10
Posted: 10/16/11 11:42 AM

93LX...

i know that people can get away with it...  but.. the least expensive 3G model alternator is like 80 bucks...

a digital volt meter is under 10 for some really cheep models.. one can pick up a decent 15 buck one at most parts stores from innova...  or even a 20 to 25 buck version..    since i work on a LOT of fuel injection systems..i had to knuckle under and buy the 100 buck version of the innova... i also have a 150 buck OTC ... a 400 buck digital hand held scope i picked up at hf a decade ago.. but when i need to know what a circuit is doing.. i need to know..

this is 2011 and the damage caused by an open charging circuit.. is just too much to chance...

dirty battery cable connections are also responsible for some alternator failures..  where the output from the alternator has not place to go but to build up voltage.. where the diodes take a hit with the voltage spike..

i am trying to drag people kicking and screaming into the new world of diagnostics..  

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9Sec93LX
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Posts: 6
Joined: 01/11
Posted: 10/17/11 10:59 AM

I understand what you are saying (you are right). It just seemed to me that the guy asking the question didn't have the money or a meter. Definitely much easier if you have one for sure. Sometimes we have to do things we don't want to/shouldn't because of tight financial situation. Like my story of swapping out the battery every morning. I was a young man just starting a family and I had to do, what I had to do.  

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hayabusa1--93lx ssp
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Posts: 24
Joined: 10/11
Posted: 10/17/11 05:06 PM

well guys i have a few meters & before i pulled the motor a few years back i had a brand new alternator put on  even though nothing was really wrong with it i still have the old one... i cant say that i've gotten around to taking car of the light issue because i think my starter was'nt lining up withit my fly wheel had to yank the pass. header twice wanted to make sure that it was set in firmly.. i will go into detail about that on another post got the starter in place started late & didnt finish up just have to tork the collector pipes up guess i'll do that on my next day off whenever that comes.. i took the red top battery to have it tested & it was pretty much right on the money course that was about 2 hours after a fresh charge  

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hayabusa1--93lx ssp
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Posts: 24
Joined: 10/11
Posted: 10/17/11 05:06 PM

well guys i have a few meters & before i pulled the motor a few years back i had a brand new alternator put on  even though nothing was really wrong with it i still have the old one... i cant say that i've gotten around to taking car of the light issue because i think my starter was'nt lining up withit my fly wheel had to yank the pass. header twice wanted to make sure that it was set in firmly.. i will go into detail about that on another post got the starter in place started late & didnt finish up just have to tork the collector pipes up guess i'll do that on my next day off whenever that comes  

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hayabusa1--93lx ssp
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Posts: 24
Joined: 10/11
Posted: 10/30/11 06:59 PM

dont know what i did out side of having to re mount the starter after finally geting it started i noticed that the light was'nt on anymore as of yet Grin  

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