C5Ryan

Came out to my car one day and noticed the battery was dead. I found this odd because it is an optima that was only about 3 months old. I hook it up to my truck and after a few minuets on the cables it finally jumps. I let the car idle for a while to get the battery charged back up and while sitting in my car with all of my doors closed I noticed the lights in my footwell are on. I automatically check the dimmer switch and it seems to be working fine. I also opened all the doors separately and the trunk as well and each time I opened one the door ajar or trunk ajar message would come up as it should. I then hooked it up to a scanner and went into the bcm and it confirmed that the doors and trunk were reading shut or open when they should. So now Im stumped because I was really thinking it was going to be a door ajar switch or something. I also noticed that the key fob isn't working, but the power door locks are working how they should. Anyone have any idea what I should check next? I am pretty sure the bcm controls everything I am having a problem with. I checked the BCM fuses and they are good. I even unplugged it for a couple minuets to see if that would reset it and no luck. Any other relays or fuses I could check? We are finally having some nice weather here in FL and Id enjoy it if I could drive my car and not worry about jump starting it every time.

C5Ryan

Car is an 03 Z06 if that helps.

Mastertvtech

I would pull the dimmer switch and verify it is opening the connection to the lights.

Vetteman Jack

Subscribed to this thread - will be curious to see what you find out.

One possibility is to contact forum member Bill Curlee and see what he can recommend. He is very knowledgeable when it comes to the C5 electrical system.

DeeGee

By dimmer switch do you mean the small rotary control to the left of the steering wheel? There's a parade setting on that which if left on can leave the interior lights on. Make sure its turned down.

If not I'd do a drain check. This might help.

Identifying Battery Problems
The C5 eats batteries unless you take some regular precautions. If your battery continually dies its either the battery which is on its last legs or something on the car.

You also need to look at how you use the car. Is it a daily driver? If so the battery should be getting a good top up every day so you may have a problem.


Is it a DD but you do short trips? If so you'll be taking a lot out of the battery every time you start. For a short trip, say less than about 20 mins, you won’t top it off properly. Eventually it'll drain.

Is it a weekend car. If so, this takes a lot out of your battery. There’s a 20MA drain even dormant. If you don’t drive the car for a reasonable time every week or so, it'll kill the battery. In this case you really do need a battery tender.

You’ll know when your battery is bad. As it gets low you may get strange electrical indications (random warnings and U fault codes). As it gets lower it may drop the memory settings or defaults such as HUD settings. Eventually you’ll get the dreaded chattering relays in the footwell and eventually the lights on the IPC will disappear.

Most batteries can be recharged quite successfully, although AGMs are harder. Start by checking the charge on the battery. Don’t read the DIC when the car is off. The value you see on the DIC is alternator output when the car is running. It will always measure an inaccurately low voltage on the battery when the ignition is off and figures of 11.0V to 11.9V is normal in this case. With the engine on, the voltmeter should show between 13V and 14.5V. You need to measure voltage across the battery terminals using a digital multi meter if possible. A fully charged battery measures 12.7V and a fully discharged battery measures 11.9V. Partially discharged batteries will give a reading somewhere in between.

If the battery is low give it an overnight charge (or put it on a battery tender until you get a fully charged indication) and retest it. A true test is under load and Autozone will do that test for free.
If you have an AGM battery like the Red Top and it has been deeply discharged it's harder to recover it. This might help:

If you’ve recharged it and it still runs down, then you need to start looking for excessive drains. Bill Curlee posted a good method for checking:

http://forums.corvetteforum.com/1567522286-post590.html

There are some common faults which are well known for causing problems:

First to check is the interior lighting rotary switch on the drivers panel. It’s possible for that to be turned on as there’s a setting (fully clockwise) which bypasses the auto off function. Turn it fully counter clockwise and check after about 30 minutes (preferably in the dark) that the interior lights have gone off.

If it’s not the lights something has failed or is badly installed.

Have you fitted an after-market device which draws current? Typically it’s a cellphone charger, radar warner or a similar device that’s the problem.

If still no joy, you need to start pulling fuses to identify the problem.

The power seat switches on the side of both seats are notoriously unreliable. The switch becomes sticky with use and can stick in the “on” position. You shouldn’t damage the motors as they are thermally protected. The fuse may blow so worth checking (Fuse 36 20A in footwell).

The driver’s lumbar motor can also cause issues so check this too (mini fuse 3 15A in footwell). The seat controls connect under the seat. Pull the connector and if the drain stops that’s your problem.

Less common but not unheard of are failures of the headlight motor control module the alternator and the Bose Amplifier under the dash on the driver’s side.

Phanni

My last red top lasted about three months, never again.


Purchased last fall.

3boystoys

My RedTop is 8+ years old-starts like new EVERY time. Keep all my toys on a trickle charger when I'm not playing with them.

rob-cyn

This obviously isn't a battery issue.
I have had nothing but good luck with Optima batteries myself.

C5Ryan

thanks for some of the suggestions. Like stated in the original post. the dimmer switch was the first thing I checked. it is not in the on position and does dim the gauges and radio etc. I did however notice when checking through some trouble codes that when I come up to RFA I have no communication. that explains why the fob isn't working and might also have something to do with the lights staying on. any suggestions on where to go with this?

3boystoys

The car should shut all the lights out no matter what after about 15 minutes, even if you leave them ALL on and shut the car off.

woodman300

if i read this right, this makes me think that the receiver that gets the key fob signal may be stuck. like when you press the door lock button and the courtesy lights come on. maybe whatever makes the lights com on is stuck and telling the lights to stay on. i don't know how they work exactly but maybe there is a stuck relay in the circuit. if i were you, i would pull the fuse for the courtesy lights so they can't come on. you don't need them anyway. then you should be able to drive it without worry of a dead battery. i think the fuse is #29 in the footwell but i am not sure about that. you can search and find though.

o2bnkc

Just my thoughts, but I think your battery is bad.

C5Ryan

I pulled relay 42 yesterday and the lights stayed on. I check out 37