Alternator bad, pod indicator lights blink intermittantly
02-26-2009, 05:25 PM
#1
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Alternator bad, pod indicator lights blink intermittantly
Hello Everyone,
I am back on rennlist after a long absence and significant degradation due partially to neglect of my 87 S4. My latest problem is electrical and I have searched this forum for answers but really found nothing. So, it started with all the indicator lights and warning lights blinking on and off intermittantly, so I stopped driving the car but still needed to move it occasionally for street cleaning. In the meantime I check fuses and relays without success. Then I noticed the alternator voltage was down around 10V... bad alternator... Well, I usually try to get the engine warmed up when I move it and I was rev'ing the engine quite high and all of a sudden the alternator started working again (over 12V) and the blinking lights stopped. I drove around a bit but then things went back to around 10V and the blinking started again. I am wondering if I have 2 electrical problems or simply need a new alternator. thanks ever so much. Also, can anyone recomend a good mechanic, for both tires/alignment and other mechanical work, in the oakland Ca, area? Mark
I am back on rennlist after a long absence and significant degradation due partially to neglect of my 87 S4. My latest problem is electrical and I have searched this forum for answers but really found nothing. So, it started with all the indicator lights and warning lights blinking on and off intermittantly, so I stopped driving the car but still needed to move it occasionally for street cleaning. In the meantime I check fuses and relays without success. Then I noticed the alternator voltage was down around 10V... bad alternator... Well, I usually try to get the engine warmed up when I move it and I was rev'ing the engine quite high and all of a sudden the alternator started working again (over 12V) and the blinking lights stopped. I drove around a bit but then things went back to around 10V and the blinking started again. I am wondering if I have 2 electrical problems or simply need a new alternator. thanks ever so much. Also, can anyone recomend a good mechanic, for both tires/alignment and other mechanical work, in the oakland Ca, area? Mark
02-26-2009, 06:26 PM
#2
Burning Brakes
Could be alternator/brushes/loose belt. Could be grounds.
Go to www.norcal928.org for a list of local shops.
Go to www.norcal928.org for a list of local shops.
02-27-2009, 01:33 AM
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Well, yes I am certain there is a problem with the alternator, but my real concern is the indicator lights blinking on and off, is that a symptom of the bad alternator or a coincidental second electrical problem. And thanks for the Norcal tip, looks like Bill has updated the mechanic listings recently! M
02-27-2009, 06:13 AM
#4
Craic Head
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It could be two isolated problems but the fact that the gauge popped up to 12 v and the blinking stopped at the same time leads me to believe they're related.
Having said that, the fact that they're related doesn't mean that it's actually an alternator problem. If you have a VOM (Volt Ohm Meter) you should test the voltage at the jump post to see what you get. The voltage gauge on the pod is not extremely accurate under the best of circumstances. That will tell you whether or not you're charging correctly or possibly just have a discharged battery that won't hold a charge, or what.
Also, if you haven't been taking care of the car, I'd go through and clean all of the grounds and remove and replace all of the relays and fuses at the CE panel, which will reduce the likelihood that it's just a bad connection there (which is very common).
Next for the pod lights (if that's what you meant by the lights flashing) it may be something as simple as the dimmer wheel under the left side of the pod. When this gets old and corroded it tends to kill the lights rather than just dimming them. Play with it a bit to clean up the contacts on it, or alternately remove the pod and try metering/jumping that out and see if there's any change.
Good luck and keep us posted on what you find!
Having said that, the fact that they're related doesn't mean that it's actually an alternator problem. If you have a VOM (Volt Ohm Meter) you should test the voltage at the jump post to see what you get. The voltage gauge on the pod is not extremely accurate under the best of circumstances. That will tell you whether or not you're charging correctly or possibly just have a discharged battery that won't hold a charge, or what.
Also, if you haven't been taking care of the car, I'd go through and clean all of the grounds and remove and replace all of the relays and fuses at the CE panel, which will reduce the likelihood that it's just a bad connection there (which is very common).
Next for the pod lights (if that's what you meant by the lights flashing) it may be something as simple as the dimmer wheel under the left side of the pod. When this gets old and corroded it tends to kill the lights rather than just dimming them. Play with it a bit to clean up the contacts on it, or alternately remove the pod and try metering/jumping that out and see if there's any change.
Good luck and keep us posted on what you find!
02-27-2009, 10:22 AM
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I suspect that the pod problem is causing the alternator problem, and that the alternator is fine.
An alternator converts rotary energy into electrical energy by moving a magnetic field (the armature) thru the coils in the housing. The magnetic field MUST be present for the alternator to generate electricity. It is initially created by the excitation current that is supplied thru the charging warning light and the parallel resistor (mounted on the back of the voltage gauge). If the excitation current is too weak (bad resistor, bad bulb, bad connection), but present, the alternator will start charging ONLY at higher RPM levels. If the excitation current is not present at all, the alternator will never charge.
Once the alternator starts charging, it supplies its own field current. Since there is now voltage on both sides of the light/resistor combo, the light goes off. Once the alternator starts charging, the light/resistor combo has no effect.
If the pod connections are bad (usually at the edge connectors), you are probably not getting the exciter current to turn the alternator on.
An alternator converts rotary energy into electrical energy by moving a magnetic field (the armature) thru the coils in the housing. The magnetic field MUST be present for the alternator to generate electricity. It is initially created by the excitation current that is supplied thru the charging warning light and the parallel resistor (mounted on the back of the voltage gauge). If the excitation current is too weak (bad resistor, bad bulb, bad connection), but present, the alternator will start charging ONLY at higher RPM levels. If the excitation current is not present at all, the alternator will never charge.
Once the alternator starts charging, it supplies its own field current. Since there is now voltage on both sides of the light/resistor combo, the light goes off. Once the alternator starts charging, the light/resistor combo has no effect.
If the pod connections are bad (usually at the edge connectors), you are probably not getting the exciter current to turn the alternator on.
02-27-2009, 11:06 AM
#6
Electron Wrangler
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I agree with Wally don't run out and buy a new alternator - I have little faith that will fix all your problems.
The alternator almost certainly isn't getting the initiation signal from the pod - that it charges at higher RPM suggests it works OK. I'd start by cleaning the pod connectors.
However another thing you might consider is describing to us in better detail exactly what is happening - you say indicator/warning lights blinking - what exactly do you mean? flashing on & off - all together? brightening & dimming - all together? I ask because in normal driving none of them should even be on... so what exactly is happening?
The indicator/warning lights all come on for buib test mode when the car is not running but the ignition is on. The car knows its not running based on the generation status of the alternator... a connection problem here can create false states... check also both connections to the alternator
Alan
The alternator almost certainly isn't getting the initiation signal from the pod - that it charges at higher RPM suggests it works OK. I'd start by cleaning the pod connectors.
However another thing you might consider is describing to us in better detail exactly what is happening - you say indicator/warning lights blinking - what exactly do you mean? flashing on & off - all together? brightening & dimming - all together? I ask because in normal driving none of them should even be on... so what exactly is happening?
The indicator/warning lights all come on for buib test mode when the car is not running but the ignition is on. The car knows its not running based on the generation status of the alternator... a connection problem here can create false states... check also both connections to the alternator
Alan
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02-27-2009, 07:54 PM
#8
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Complete top to bottom review of 14 pin connector, in addition to grounds + ign. switch.
Consider pulling a few fuses, also. If you see a lot of corrosion, pull the whole panel and clean contacts + replace corroded fuses.
Might as well start with all this stuff, then progress to alternator, unless you've done it all recently.
When battery is real low it causes problems. Disconnecting and charging would be another option for first thing to do.
Also, I've had one situation where the alternator hose got packed with nut shells by mice, then the shells worked their way against the spinning part of the alternator and destroyed some of the connections to the diodes....
Sounds like a leisurely Saturday with beverage in one hand and quarter inch ratchet in the other.
Consider pulling a few fuses, also. If you see a lot of corrosion, pull the whole panel and clean contacts + replace corroded fuses.
Might as well start with all this stuff, then progress to alternator, unless you've done it all recently.
When battery is real low it causes problems. Disconnecting and charging would be another option for first thing to do.
Also, I've had one situation where the alternator hose got packed with nut shells by mice, then the shells worked their way against the spinning part of the alternator and destroyed some of the connections to the diodes....
Sounds like a leisurely Saturday with beverage in one hand and quarter inch ratchet in the other.
02-28-2009, 08:49 PM
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Wow! as usual the 928 community rocks! I'll check the pod connectors tomorrow. I had checked the fuses and potential culprit relays already. I hadn't thought about the initial alternator charge issue. The battery is new and has been on a charger so it is fully charged and ok when I am checking things. Mark
Oh, and the lights that blink on and off are the warning lights. Tomorrow I'll write down all of the ones that blink and look at things with an eye to provide a better description. thanks again!
Oh, and the lights that blink on and off are the warning lights. Tomorrow I'll write down all of the ones that blink and look at things with an eye to provide a better description. thanks again!
02-28-2009, 11:55 PM
#11
Three Wheelin'
If a person wanted to test the alternator in the car what would be the easiest way?
Use a volt meter, but where would you check for voltage?
Maybe a 12VDC jumper to; where on the alternator to energize the field?
Would a resistor be needed to for this test and if so what resistance?
Anyone?
Use a volt meter, but where would you check for voltage?
Maybe a 12VDC jumper to; where on the alternator to energize the field?
Would a resistor be needed to for this test and if so what resistance?
Anyone?
03-01-2009, 12:22 AM
#12
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First test is to hook a voltmeter to the jump start terminal (plastic cap on the left fender well) and engine ground. You should see battery voltage. Crank the engine, rev to 2000 rpm. You should see 13.8-14.6 vdc.
If no increase, first check is the 14-pin connector near that jump start terminal. Clean all of the connections. Be careful to not let it fall apart! Retest as above. If still no joy, you can check for voltage on the alternator exciter circuit. On Mark's '87, that would be the blue wire in pin #1 of the 14-pin connector. If there is no voltage, you can touch a jumper from the blue wire to the jump start terminal with the engine running. If the jump start voltage is then 13.8-14.6 vdc, the alternator is working, and the problem is a bad connection in the exciter wire or on the ignition switch.
Since T-MaX didn't tell us what year his/her car is, I can't give any specific check. It is a really good idea to have the full info on your car in your signature, or give it each time. Lots of differences from '79 to '95!
If no increase, first check is the 14-pin connector near that jump start terminal. Clean all of the connections. Be careful to not let it fall apart! Retest as above. If still no joy, you can check for voltage on the alternator exciter circuit. On Mark's '87, that would be the blue wire in pin #1 of the 14-pin connector. If there is no voltage, you can touch a jumper from the blue wire to the jump start terminal with the engine running. If the jump start voltage is then 13.8-14.6 vdc, the alternator is working, and the problem is a bad connection in the exciter wire or on the ignition switch.
Since T-MaX didn't tell us what year his/her car is, I can't give any specific check. It is a really good idea to have the full info on your car in your signature, or give it each time. Lots of differences from '79 to '95!
03-01-2009, 01:21 AM
#13
Three Wheelin'
1989 S4, sorry wally, I (he) keep forgetting my sig is no long present.
Cheers, T
p.s.
I think only Ren-members get sigs
, Take a look at my location under my avatar 
Cheers, T
p.s.
I think only Ren-members get sigs
, Take a look at my location under my avatar
03-01-2009, 12:25 PM
#14
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The easiest place to check on the '89 is the same blue wire on pin #1 of the 14-pin connector. This wire connects to M13 on the plugs on the Central Electric Panel, so make sure that the plugs are all tight.
03-01-2009, 01:22 PM
#15
Wally and Alan are way ahead of me here. Follow through with their methodology. Just a note; if the alternator ever fails to perform as it should, the brushes/voltage regulator assembly is not expensive depending on where you buy it from and is simple to replace.