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'Alternator circuit open or shorted,' 1993 Grand Caravan



 
 
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  #1  
Old December 4th 07, 08:46 PM posted to rec.autos.tech
Greg Bailey
external usenet poster
 
Posts: 12
Default 'Alternator circuit open or shorted,' 1993 Grand Caravan

Hi, I've got a 1993 Dodge Grand Caravan, 170k miles, still in great shape
bodywise and mechanically, still some life left in the old girl.

Couple of months ago, I noticed the gas mileage going south, then the "Check
Engine" light came on. Had it checked out, the EGR valve and coolant
temperature sensor needed replacing.

Since then it's run fine, gas mileage has been much better even around town,
engine has seemed like it had a bit more get up and go.

Yesterday morning was the first real cold morning we've had since getting
the car worked on (am in the Deep South). When I cranked the van up to take
the kids to school, the "Check Engine" light came on. I turned the engine on
and off and it cleared that out and I didn't see it again the rest of the
day. Did a lot of running around in the van and it ran fine.

This morning, it was even colder. Cranked the van up and let it warm up,
everything was fine, no "Check Engine" light. Did some more running around
town, turned the van on and off several times. After my next-to-last stop,
however, when I got back in and cranked her up, the "Check Engine" light
came on and stayed on, and now will not go off.

My main mechanic was not available today so I took it to another mechanic
who I knew had a SnapOn machine and the only code it was throwing was
"alternator circuit open or shorted."

The alternator is working and charging absolutely perfectly and the mechanic
did a quick check for shorts on it, on the battery and on all the fuses
inside. Everything checks out fine.

He said this is likely in the computer and that I'd have to take it to a
dealership to have them look at it. I'd really prefer not to, both from the
cost standpoint and the fact that they're probably not going to be overly
thrilled about me rolling in this 14-year-old van with 170K miles on it,
they'd probably prefer I buy a new one which is not going to happen at the
moment.

The mechanic said the computer might need to be replaced and pointed to some
stuff down around the battery area ... sorry to be so indefinite, with my
meager knowledge of all the parts of the car, I'm not quite sure what he was
talking about ... said check with junkyards to try to find replacements.

He also said that as long as the alternator was charging as it was, we were
in no real danger of being stranded anywhere and that the light would be
only a nuisance.

Can anyone give me any more specific ideas about what might be going on
here, what I might need to have replaced to take care of this and maybe some
reassurance that this is not a really dangerous situation, because having
been stranded 90 miles from home one time when an alternator died, that
concern is always in the back of my mind.

Thanks in advance for any help.



Ads
  #2  
Old December 5th 07, 05:55 PM posted to rec.autos.tech
Mike Walsh
external usenet poster
 
Posts: 101
Default 'Alternator circuit open or shorted,' 1993 Grand Caravan


The alternator could have an intermittent problem, maybe with the voltage regulater. If you have a voltmeter in the dash you can watch it for fluctuations. You can buy a voltmeter that plugs into the cigarette lighter if you don't have a voltmeter in the dash.

Greg Bailey wrote:
>
> Hi, I've got a 1993 Dodge Grand Caravan, 170k miles, still in great shape
> bodywise and mechanically, still some life left in the old girl.
>
> Couple of months ago, I noticed the gas mileage going south, then the "Check
> Engine" light came on. Had it checked out, the EGR valve and coolant
> temperature sensor needed replacing.
>
> Since then it's run fine, gas mileage has been much better even around town,
> engine has seemed like it had a bit more get up and go.
>
> Yesterday morning was the first real cold morning we've had since getting
> the car worked on (am in the Deep South). When I cranked the van up to take
> the kids to school, the "Check Engine" light came on. I turned the engine on
> and off and it cleared that out and I didn't see it again the rest of the
> day. Did a lot of running around in the van and it ran fine.
>
> This morning, it was even colder. Cranked the van up and let it warm up,
> everything was fine, no "Check Engine" light. Did some more running around
> town, turned the van on and off several times. After my next-to-last stop,
> however, when I got back in and cranked her up, the "Check Engine" light
> came on and stayed on, and now will not go off.
>
> My main mechanic was not available today so I took it to another mechanic
> who I knew had a SnapOn machine and the only code it was throwing was
> "alternator circuit open or shorted."
>
> The alternator is working and charging absolutely perfectly and the mechanic
> did a quick check for shorts on it, on the battery and on all the fuses
> inside. Everything checks out fine.
>
> He said this is likely in the computer and that I'd have to take it to a
> dealership to have them look at it. I'd really prefer not to, both from the
> cost standpoint and the fact that they're probably not going to be overly
> thrilled about me rolling in this 14-year-old van with 170K miles on it,
> they'd probably prefer I buy a new one which is not going to happen at the
> moment.
>
> The mechanic said the computer might need to be replaced and pointed to some
> stuff down around the battery area ... sorry to be so indefinite, with my
> meager knowledge of all the parts of the car, I'm not quite sure what he was
> talking about ... said check with junkyards to try to find replacements.
>
> He also said that as long as the alternator was charging as it was, we were
> in no real danger of being stranded anywhere and that the light would be
> only a nuisance.
>
> Can anyone give me any more specific ideas about what might be going on
> here, what I might need to have replaced to take care of this and maybe some
> reassurance that this is not a really dangerous situation, because having
> been stranded 90 miles from home one time when an alternator died, that
> concern is always in the back of my mind.
>
> Thanks in advance for any help.


--
Mike Walsh
  #3  
Old December 5th 07, 06:09 PM posted to rec.autos.tech
AZ Nomad
external usenet poster
 
Posts: 249
Default 'Alternator circuit open or shorted,' 1993 Grand Caravan

On Wed, 05 Dec 2007 11:55:08 -0500, Mike Walsh > wrote:

>The alternator could have an intermittent problem, maybe with the voltage regulater. If you have a voltmeter in the dash you can watch it for fluctuations. You can buy a voltmeter that plugs into the cigarette lighter if you don't have a voltmeter in the dash.


1) quit top posting, set your damn margins, and learn how to trim what you
quote.

2) the voltmeter trick won't tell you if the problem is the alternators
components (and wether it is field coils, brushes, diodes, regulator, etc.),
alternator belt, alternator wiring, battery wiring, fusebox wiring, or
even a lousy cigarette lighter socket.

You need an oscilloscope to even to a half assed job of alternator diagnoses.

Quit wasting time. Take the damn car into a shop with some real test
equipment. If the problem is intermittant, wait for it to happen, and then
rush to the nearest autozone (or equiv.) store and have them run the test.
  #4  
Old December 5th 07, 06:13 PM posted to rec.autos.tech
cavedweller
external usenet poster
 
Posts: 212
Default 'Alternator circuit open or shorted,' 1993 Grand Caravan

On Dec 5, 12:09 pm, AZ Nomad > wrote:
intermittant, (sic)

Like this?

  #5  
Old December 7th 07, 04:09 PM posted to rec.autos.tech
Steve[_1_]
external usenet poster
 
Posts: 3,043
Default 'Alternator circuit open or shorted,' 1993 Grand Caravan

Mike Walsh wrote:
> The alternator could have an intermittent problem,


Yes, the rotor winding could be intermittently opening, OR the brushes
could be worn to the point that they occasionally lose contact with the
sliprings.

maybe with the voltage regulater.

Voltage regulator is in the computer, and they almost never fail
(occasionally they do, but they're about the last thing to check).
Another possibility is an intermittent connection on the big plug that
goes into the computer.

  #6  
Old December 7th 07, 04:17 PM posted to rec.autos.tech
Steve[_1_]
external usenet poster
 
Posts: 3,043
Default 'Alternator circuit open or shorted,' 1993 Grand Caravan


>
> 2) the voltmeter trick won't tell you if the problem is the alternators
> components (and wether it is field coils, brushes, diodes, regulator, etc.),
> alternator belt, alternator wiring, battery wiring, fusebox wiring, or
> even a lousy cigarette lighter socket.


Agreed there.

>
> You need an oscilloscope to even to a half assed job of alternator diagnoses.


Horse****. If you take a step-by-step approach and work your way through
the system, you can solve any alternator problem with a good multimeter
and a thorough understanding of how the system works. WTF good would a
damn OSCILLOSCOPE be for alternator troubleshooting anyway??? I've got a
master's degree in electrical engineering and I can't for the life of me
figure out why I'd pick an O-scope to troubleshoot an alternator. Maybe
I should use a $15,000 spectrum analyzer too, then I could detect an
extra frequency component in the ripple voltage and that might give me a
3rd-hand hint that a diode is bad.

OR, I could just test the stinking diodes with a $100 Fluke meter and be
done with it. Heck, even a $30 generic brand multimeter would be plenty
good for that.

Sheesh, talk about mountains out of molehills....
>
> Quit wasting time. Take the damn car into a shop with some real test
> equipment. If the problem is intermittant, wait for it to happen, and then
> rush to the nearest autozone (or equiv.) store and have them run the test.


Yeah. Autozone- there's a real brain trust for you. :-/

  #7  
Old December 10th 07, 11:51 AM posted to rec.autos.tech
Tim[_11_]
external usenet poster
 
Posts: 6
Default 'Alternator circuit open or shorted,' 1993 Grand Caravan

Greg Bailey wrote:
> Hi, I've got a 1993 Dodge Grand Caravan, 170k miles, still in great shape
> bodywise and mechanically, still some life left in the old girl.
>
> Couple of months ago, I noticed the gas mileage going south, then the "Check
> Engine" light came on. Had it checked out, the EGR valve and coolant
> temperature sensor needed replacing.
>
> Since then it's run fine, gas mileage has been much better even around town,
> engine has seemed like it had a bit more get up and go.
>
> Yesterday morning was the first real cold morning we've had since getting
> the car worked on (am in the Deep South). When I cranked the van up to take
> the kids to school, the "Check Engine" light came on. I turned the engine on
> and off and it cleared that out and I didn't see it again the rest of the
> day. Did a lot of running around in the van and it ran fine.
>
> This morning, it was even colder. Cranked the van up and let it warm up,
> everything was fine, no "Check Engine" light. Did some more running around
> town, turned the van on and off several times. After my next-to-last stop,
> however, when I got back in and cranked her up, the "Check Engine" light
> came on and stayed on, and now will not go off.
>
> My main mechanic was not available today so I took it to another mechanic
> who I knew had a SnapOn machine and the only code it was throwing was
> "alternator circuit open or shorted."

First off it doesn't matter what machine you use.
the problem is that your alternator is PCM controlled so the alternator
can be in great shape and the car still won't charge. The light on your
dash is a good indicator.
As you can see by the responses you got, great mechanics have a problem
with these type of situations.

Find a good shop that ONLY works on Alternators and Starters and have
them bypass the pcm with a regulator. this will work just fine and save
you the cost of buying a computer for your car.
>
> The alternator is working and charging absolutely perfectly and the mechanic
> did a quick check for shorts on it, on the battery and on all the fuses
> inside. Everything checks out fine.
>
> He said this is likely in the computer and that I'd have to take it to a
> dealership to have them look at it. I'd really prefer not to, both from the
> cost standpoint and the fact that they're probably not going to be overly
> thrilled about me rolling in this 14-year-old van with 170K miles on it,
> they'd probably prefer I buy a new one which is not going to happen at the
> moment.

I work at a shop that only does electrical work on cars and trucks.
This is a very common problem we see.
>
> The mechanic said the computer might need to be replaced and pointed to some
> stuff down around the battery area ... sorry to be so indefinite, with my
> meager knowledge of all the parts of the car, I'm not quite sure what he was
> talking about ... said check with junkyards to try to find replacements.

Just get the pcm bypassed.
>
> He also said that as long as the alternator was charging as it was, we were
> in no real danger of being stranded anywhere and that the light would be
> only a nuisance.
>
> Can anyone give me any more specific ideas about what might be going on
> here, what I might need to have replaced to take care of this and maybe some
> reassurance that this is not a really dangerous situation, because having
> been stranded 90 miles from home one time when an alternator died, that
> concern is always in the back of my mind.


We at PASCO are your starting and charging specialists
410-546-2041
>
> Thanks in advance for any help.
>
>
>

 




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