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97 Eldorado
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48 Posts
Discussion Starter #1
I am having a very strange problem. Last May, my car started acting like this but I never did anything about it until I read these forums. Sometimes when I drive the car, all of a sudden the traction control light comes on, the theft system problem comes up, the PRD321 lights go off and the needles on my gauges go crazy. It did not happen often so I did nothing about it until last week when I replaced the battery thinking it was because of a weak battery. The problem is still there and it happens more often. I have been monitoring the battery volts and from what I can tell, it happens when the volts go low around 12.4 or lower. Sometimes the car runs at 13.4 or 13.1 volts and it runs great. Most of the time it starts at 12.9 and eventually gets lower to 12.2 or so and then the problems start. Also, before it happens, I can almost feel the traction control in the brake pedal trying to engage. Then the lights come on. However, only at low voltage. I took it to PepBoys to test the system and they said my alternator is bad. Any suggestions before I get a new alternator put into it? Thanks
 

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2002.5 F55 CORSA STS, 2014 Explorer XLT FWD
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69,119 Posts
Yep...ACDelco. Look at your DIC codes and I'll bet you find a slew of "low voltage" history codes along with the current system codes. While you're at it, now's the time to go on a witch hunt for corroded/poor connections in the battery cable/charging circuits.
 

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97 Eldorado
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48 Posts
Discussion Starter #4
Ok. Well I am not putting it in myself. I got an estimate for $370. He said that AC Delco is not necessary. He quoted me for an alternator that is $207. How much is an AC Delco? What I was really asking is if you guys think that my problem sounds like an alternator issue. Trouble codes are:

U1016
B2477
B2471
P0603
B2750

Thanks
 

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Sedan de Ville, CTS
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4,764 Posts
Aftermarket alternators and compressors are junk. Many are bad right out of the box. Look for an ACDelco distrib or a dealer that will give you a discount.

You will incur the labor again and again by using Azone, OReilley, and Advance, etc in my opinion.
 

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White Diamond '03 DHS (with DTS floor shift)
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86,987 Posts
Since the battery was replaced and the alternator was diagnosed as a problem, I would tend to agree that it IS the alternator.

Check http://www.rockauto.com or http://www.gmotors.com for A/C Delco prices.

If he gives you a lifetime warranty on the aftermarket alternator, make sure it includes labor, but I'd still go with the Delco.
 

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97 Eldorado
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48 Posts
Discussion Starter #7
sorry for not posting for a while. all of this stuff happened almost a month ago. well, i went to a local, reputable service center to have a new alternator put into it. they said they they would check the system first to see if it is not the alternator. sure enough, the alternator passed their test. they showed me a print-out from a d-tach machine and the starter and alternator passed while the battery tested bad. they told me to go back to pepboys because they gave me a bad battery. so, i go to pepboys and they say, we have to test it before we give you a new battery. they tested it and showed me. the battery tested fine on their machine and it was flashing "low charging system." i said, i have a print-out stating the battery is bad. then i noticed the battery was leaking. so, he had to give me a new battery. he also said that the warranty on the new one is void until i have documentation from the dealer stating that the alternator is fine. so i drove it home and it was fine for about 4 days. then, the same exact problems were happening again. it is getting worse so today i just dropped it off at the dealer. I cannot wait to find out what is wrong with it. i want another opinion on it even if it costs me $85/hr. to look at it. if it is the alternator, should i just have the dealer replace it?
 

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White Diamond '03 DHS (with DTS floor shift)
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86,987 Posts
May as well. It is there and they'll usually apply the diagnostic fee to the repair.
 

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97 Eldorado
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Discussion Starter #9
well, the dealer just called and it is the alternator. i am not happy with the place who told me that it was just the battery. also, they said the battery cables are corroded and that they will clean them. the total with the AC Delco alternator is $665 with tax!!!! at least my car will be fixed.........when i get the car tomorrow, where should the volts run? around 14? what is a good way to make sure the car is fixed correctly? thanks
 

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97 Eldorado
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Discussion Starter #10
now they just called me and said that they put a new alternator in and it is only putting out 5 volts. they said that they checked all the wiring and it is fine. so they think that the part they put in was bad. they said they will try another one tomorrow. does that sound like it was just a bad alternator?
 

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97 Eldorado
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48 Posts
Discussion Starter #13
well, that's what it was: a bad part. got the car back today with a new alternator and when i started it up it was at 14.2. the voltage varied slightly when i would turn on the a/c or whatever. when i would press the brakes to slow down from a faster speed, the volts drop a little but then go right back up when i let off of them. is that normal? thanks guys
 

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2002.5 F55 CORSA STS, 2014 Explorer XLT FWD
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:cursin: I'll do this song and dance one more time. A fully charged 12V flooded lead-acid battery shows just about 12.6 volts, open circuit, no load for over a half hour. A dead battery shows 11.9-12 volts, but that's plate surface voltage: there's nothing in reserve. An alternator/regulator typical of automotive use puts out around 14.2-14.7 volts at a decreasing amperage rate, depending on battery charge state. That voltage may go lower at low/stop speeds due to engine rpm and accessory load. That voltage is also designed to slightly overcharge a battery preventing the buildup of lead sulphate on the plates, which is what kills batteries. As a battery charges, its internal resistance increases, so the alternator sensing circuits adjust the regulator to.........duh, regulate voltage and amperage. A discharged battery appears as an almost dead short to the alternator, requiring vast amounts of charging amps, thus heating and destroying the alternator. High charge rates account for the alternator "whine" you sometimes hear after a layup period. The liquid (electrolyte) in a discharged battery is almost pure water because the sulphuric acid is formed into lead sulphate in/on the plates. That's why a dead battery will freeze and pop open. Keep your connections clean and your powder dry. Whew !!!
 

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97 Eldorado
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Discussion Starter #16
hey sorry i haven't ever replied to this. i have been driving the car now for 2 months with the new alternator and it runs at 14.5 volts. so, that was the problem. i no longer get the theft system problem message and the traction control light does not go on. it was a very annoying problem. i guess these cars are extremely sensitive to low voltage.
 

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1996 Cadillac Fleetwood Brougham
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4,414 Posts
Interesting note .....While my voltage readings showing 14.8 , I swiched on the seat heaters but the voltage readout not changed .I presumed it should have changed .
 

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99 Seville STS, 08 STS4 N* 1SG F55
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Interesting note .....While my voltage readings showing 14.8 , I swiched on the seat heaters but the voltage readout not changed .I presumed it should have changed .
If your voltage HAD changed that could be the sign of a problem. The voltage regulator in the alternator is designed to maintain a constant voltage regardless of the load. It is the current output that changes depending on how much stuff is turned on. It you had every electric circuit engaged on the car it should still put out the same voltage (or a very small deviation if you're running at the rails of alternator output).
 

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1996 Cadillac Fleetwood Brougham
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4,414 Posts
If your voltage HAD changed that could be the sign of a problem. The voltage regulator in the alternator is designed to maintain a constant voltage regardless of the load. It is the current output that changes depending on how much stuff is turned on. It you had every electric circuit engaged on the car it should still put out the same voltage (or a very small deviation if you're running at the rails of alternator output).
Cool info, thanks
 
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