crowz

Since I bought my vette back in December its drained the battery to 0 volts every couple of days. I finally got a chance to test it to see how many amps I had draining.

2.64 amps

I pulled every fuse, every breaker in the fuse box and no change.

Pulled every relay I could find under the hood, unplugged the headlights, wiper motor, etc.

Still 2.64 to 2.66.

Suggestions on what might pull that much?

I changed stereos since buying it and it didn't change the running down the battery any. No amp just radio in dash.

playsdixie

sounds like the draw from the cts circuit=like when you open the door...you know when you put the battery in series with your meter, it opens that circuit......also you could try looking at it in the dark....spare tire lite, mirror lites/glove box open could cause this....

crowz

The door lights, mirror lights, cargo area and glove box light isn't it. Is there a spare tire light on a convertible?

The door light timer should be on a fuse too right? Removed all fuses and no effect.

Hot Rod Roy

Same question that's been asked 10,000 times . . . What year?

Have you tried disconnecting the alternator?

crowz

1987 convertible automatic

I disconnected the alternator also and its been replaced since buying the car too.

s carter

you say you have pulled every fuse, breaker, so on and other components. All at the same time?

because I start to suspect a short. the earlier C-4 automatics had a problem of a mold flashing on the trans cutting into the harness behind the Distributor. I think the problem had been fixed by 87 but give it a look.

then I would start chasing the power lines from the battery to starter and the power supply line to fuse box and the supply to the Ignition switch.

Cliff Harris

Many circuits are powered by fusible links from the "jump start" terminal behind the battery. Disconnect those and check for current draw on each one.

crowz

That's my next target. Probably will do that tomorrow. We spent most of the day just driving it today. First time the wife and I had a chance to go on a drive with the top down. Was awesome

gerardvg

Hi

dont forget the antenna, that has power to it all the time.
You may hear a click every minute or so, that happened to my antenna it was jamming the antenna motor ties to run then trips the overload.
That would flatten the battery over a couple of days.

Removed the antenna motor greased it and reassembled all good since, something worth checking. Same goes for the headlight motors.

crowz

Antenna works correctly so Im guessing its good.

I unplugged the headlights to test for that already.

crowz

Update:

Pulled all the wires loose from the distribution gizmo behind the battery.

ALL the wires except one caused the 2.60 amp drain.

WTF

This is beyond weird. There were 7 wires there. What is on the same circuit as all of them but one that could do that?

c4cruiser

That amperage is a huge drain. There should only be a small (.2mA or less) drain with everything shut down.

Did you remove all of the fusible links from the distribution block and then re-attach each one by itself to check for the current drain? Those fusible link wires provide power to the major electrical systems of the car. I would suggest getting the FSM book set for the '87. There are complete wiring diagrams for the electrical systems including pages showing the power distribution for the 7 (8 if the car has the Aux Cooling Fan) fusible links.

crowz

I pulled all the wires off and touched each one to the wire from the battery that goes to that point. ALL the wires but one caused the 2.6 amp draw. Blew my mind.

I pulled all the fuses yesterday one at a time and had no effect. Im going to pull all the fuses at one time in a few minutes and see if that effects anything.

At first it was a "I'll put a disconnect on it if I cant find it".

Nope its on now. I WILL find whats draining it if I have to rebuild the entire car

c4cruiser

There are a number of systems that take power from one of the smaller red wires that connect to the positive cable.

One of those two wires go directly to the jumper block from the positive battery cable. The other goes to another (separate) fusible link that provides power to the cooling fan relay. If your car has the auxiliary cooling fan located in front of the A/C condenser, there will be a second fusible link to the relay that controls that fan. Both of those fusible link wires will be orange.

That same wire will also have a fusible link (red) that goes to these items:
Oil pressure switch
Fuel Pump Relay
Mass Burn Off Relay
Mass Burn Off Control Relay (both of these are on the firewall above the jumper block)
ECM

My '87 FSM shows all of the wires going to those devices as Orange in color.

crowz

Fusible link H, E and D are eliminated since they were still connected when I disconnected the wire to the jump block and the load went away.

That leaves J, G, K, B, C, M, A, and F.

crowz

Update

Removed all fuses and breakers from the fuse panel at one time. No effect.

Now removing dash panels.

Will disconnect all stereo wires (there is a rats nest from the previous owner around the radio harness) and also try removing relays and anything else fuse-ish behind where the bread box goes. Will be putting a bread box panel back in place of the homemade flat panel crap the previous owner did.

VikingTrad3r

there are some fuses and relays behind the stereo and the hvac control, the center panel of the dash panel. Maybe even behind the idiot light thing too.

crowz

Well bread box is installed. That was fun in itself. The a/c ducts had contracted after being connected to the vent with it being so much closer to the dash. Couldn't get the duct reconnected after putting the breadbox in place.

Thank god see4parts sent a hose with the breadbox I bought from him or I would of never of been able to connect the thing. Note for people to remember. If you have a/c ducting for spares find some way to keep them stretched or over time they will never stretch back out when needed.


Anyways removing the stereo and disconnecting the radio wiring mess made no difference.

Fixing to unplug the climate control unit next. Old self started giving out so came inside for a break

crowz

Ok its dark so its time to call it quits for the night. Will start on it again tomorrow.

WVZR-1

I don't know if I overlooked anything else or not but if this car has C68 ATC I believe the blower module is powered directly from a fusible link to the starter motor. In later years if the blower module was bad the fan runs all of the time. I'm not sure what happens with an early C68 car. Disconnect/unplug the blower module I'd think much easier than removing fusible link from the starter motor.

Red wire at the blower module is a direct feed from the starter motor if the FSM image posted earlier might be in error.

An '86 is wired this way and I'd think an '87 done similarly. The FSM image earlier doesn't seem to agree with this but I'd think it easier to just assume maybe it is similar to the '86 and unplug the module to confirm.

Later years are also done to the starter motor. I checked a '90 FSM.