C5 corvette electronics going crazy... And won't start
01-28-2015, 04:31 PM
#81
Melting Slicks
01-28-2015, 06:23 PM
#83
Drifting
There is no drop in the car when connected, if the battery is good and fully charged. The car's resting electronic drain is about 20-25 milliamps, so a healthy battery will maintain it's voltage for weeks and weeks and weeks if just left sitting there. Obviously with a higher current drain it will slowly discharge at a faster rate. But 12.4V is only a 75% charge, it has lost 25% of it's capacity. It may start the car once or twice, but don't go for a prolonged ride with the lights on, radio blaring, heat/AC fan running, and let it sit overnight in the cold and try to start it again. One day you will be stuck and need a jumpstart. It's possible to drain that battery faster than you are able to recharge it, and it's not charging well to begin with.
01-28-2015, 07:37 PM
#84
Melting Slicks
My 8-month-old Bosch has measured 12.48-12.52 in-car since the day I put it in. Some day when I'm bored enough or have some other reason to pull the ground cable, I'll see what difference it makes.
01-28-2015, 07:52 PM
#85
Drifting
The measurement on the DIC is not the same as measured directly from the battery (is often lower), but the battery voltage measured directly from the battery terminals should be the same whether connected or disconnected if the car is healthy with no excessive current draw, like from a relay or light still on, etc.
01-28-2015, 08:11 PM
#86
Melting Slicks
The measurement on the DIC is not the same as measured directly from the battery (is often lower), but the battery voltage measured directly from the battery terminals should be the same whether connected or disconnected if the car is healthy with no excessive current draw, like from a relay or light still on, etc.
(facepalm) Of course that means the underhood light is on and the interior lights, since I have to open the door to pop the hood.
Never mind. I'll try it again after the lights shut off.
01-29-2015, 11:06 AM
#88
Melting Slicks
(not the OP)
Just checked mine, after sitting overnight; yesterday all it got was a 3-mile round trip to the gym. Got 12.47 initially, which is about what I consider "normal". When the interior lights went out, it jumped to 12.56, then crept up to 12.59 over the next minute or so. (I have an LED underhood bulb, so I doubt that makes much difference.)
I'm wondering how many other people have been fooled by checking the voltage while the interior lights were still on.
Just checked mine, after sitting overnight; yesterday all it got was a 3-mile round trip to the gym. Got 12.47 initially, which is about what I consider "normal". When the interior lights went out, it jumped to 12.56, then crept up to 12.59 over the next minute or so. (I have an LED underhood bulb, so I doubt that makes much difference.)
I'm wondering how many other people have been fooled by checking the voltage while the interior lights were still on.
01-29-2015, 11:57 AM
#89
Burning Brakes
After reading the post/thread and seeing a number of good response answers I just don't understand why the OP simply won't take the battery he bought in July and take it back and get it replaced while under it's pro-rated warranty and exchange it, or upgrade, and eliminate the one crucial element to one of his two or three problems for near or no cost. Just a observation and my $0.02. Hope you get the problem resolved, electrical issues are/can be a pain in the ***. 
01-29-2015, 12:04 PM
#90
Le Mans Master
After reading the post/thread and seeing a number of good response answers I just don't understand why the OP simply won't take the battery he bought in July and take it back and get it replaced while under it's pro-rated warranty and exchange it, or upgrade, and eliminate the one crucial element to one of his two or three problems for near or no cost. Just a observation and my $0.02. Hope you get the problem resolved, electrical issues are/can be a pain in the ***.
01-29-2015, 02:57 PM
#91
Safety Car
Thread Starter
I didn't drive the car yesterday. It sat overnight the last two nights. It was in the 20's each night.
Car cranked fine, and drove fine this morning. I'm sure it will do the same on the way back home.
01-29-2015, 03:27 PM
#92
Instructor
Member Since: Feb 2014
Posts: 117
Likes: 0
Received 0 Likes
on
0 Posts
So I've been having some issues with my 97 c5. I didn't drive the car for about a week, then when I fired it up I got the "charge system fault" and "low voltage" messages. So I figured it was my ignition switch (I had cleaned up the contacts before and it fixed my issues). So I did that, and reinstalled and my car was still telling me it had low voltage. So I tested the voltage on the rear of the alternator and it was only about 3 volts. I then went and got my alternator tested. They told me my regulator was bad. I then replaced the regulator/brushes myself (I was able to buy it online). So after I replaced it I took my alternator back to get tested, and they told me it is working. Now I have everything hooked back up to my car, and I am still showing about 9.7 volts on the dash, 3 volts on the alternator, and 10.5 on the battery while running. Now my car won't even start. My batter says it has 11.5 when the car is off. I also have a relay that is making a buzzing sound. And I believe I have another relay in passenger floorboard doing the same. My car is so dead though that it won't buzz for very long for me to get down there and see which one.
I'm thinking I need to try to either clean up the ignition switch, or buy a new one. And replace the relay. What are your thoughts?
I'm thinking I need to try to either clean up the ignition switch, or buy a new one. And replace the relay. What are your thoughts?
01-29-2015, 03:32 PM
#93
Instructor
Member Since: Feb 2014
Posts: 117
Likes: 0
Received 0 Likes
on
0 Posts
01-29-2015, 04:33 PM
#94
Burning Brakes
OP stated that he had it 'tested' at three different stores, but he 'never' mentioned if he bought the battery from any of these stores. As properly stated in another post, the battery can show having a decent charge but we don't know how they tested it or whether they put load on it. I had a similar issue with Sears batteries a few years ago, they always exchanged them after being tested under a load and found each battery to have one bad cell, (new Batteries!),you never know.
01-29-2015, 04:55 PM
#95
Drifting
The OP has had much good advice which he tends to ignore and will do what he thinks is best, so let him be. If he knows that his battery was "tested" (but doesn't care to know how), and he is satisfied, good for him. But there is no way a battery with a resting voltage of 12.39V is "good", whether or not he is able to start his car. Given enough time, guaranteed, he'll be back. Maybe next time asking about where to get a new alternator, or how to control the fire in his engine compartment from overheated wiring. How do you explain why the battery won't fully charge, why jumping the wiring can solve the problem, why possibly a fusible link might blow? He's not even interested in all that, his car starts, the DIC reads his alternator output as being OK, so he's happy. Let him be, end this thread.
Last edited by mrlmd; 01-29-2015 at 04:58 PM.