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Topic: Electrical Short

in Forum: C4 Electrical


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Electrical Short (1/5)
 7/2/11 3:41pm
VetteL98
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, - Canada

Vette(s):
1988 White coupe with saddle interior


Joined: 5/2/2011
Posts: 2

I have an electrical short that can drain my battery over a three day period. I tested for a short, with a probe, at the fuse panel. With the ignition off I registered power on the Crtsy circuit and the LCD circuit. I believe that the Crtsy circuit is supposed to have power, but don't know whether there should or why there would be power to the instrument panel when the ignition is off. Does anyone have any insights or suggestions. 
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Electrical Short (2/5)
 7/2/11 9:44pm
eddie20890
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lanoka harbor, NJ - USA

Vette(s):
1990 L-98 white/ red/black leather interior targa top auto 1975 L48 blue/black leather interior t tops auto


Joined: 3/22/2009
Posts: 1363

is there anything else on that circuit like a clock?i dont have the same instrument panel as you so i cant check mine. could be something else doing it unless you pulled the fuse and let the car sit for a longer period than three days and it started. how old is the battery? an older battery can do it. dont forget there are more electrical systems in these cars. another thing you may want to check is the output of the alternator.when mine did it the output was about 13.7 volts which a friend who scanned it for me (after i bought it) said it was kind of a low reading. replaced it and stopped having the problem.
eddie208902011-07-02 18:45:42

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Electrical Short (3/5)
 7/4/11 8:38am
redvette89
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Huron, OH - USA

Vette(s):
1989 Red Convertible - 160,000 fun-filled miles -


Joined: 12/5/2009
Posts: 179

on my '89 dash panel, there's constant power to the dash panel and I believe it's for the climate control memory settings - temp, fan speed, etc. I think the '88 panel is the same

coincidently, my 2 year old battery wasn't holding a charge for more than a week this spring. like you I looked at other things as being the cause and found nothing, so I got a new battery and all is well. previous battery was a name brand and came from wally-mart on sale. this time i went back to a Napa battery.
 
good luck and keep us posted - everybody appeciates hearing the conclusion to any problem
 


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Electrical Short (4/5)
 7/4/11 11:14am
Adams' Apple
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Duncanville, TX - USA

Vette(s):
1985 Coupe-L98/Auto,Bright Red/Carmine. 1974 Coupe-L48/4speed, Medium Red Metallic/Black Deluxe.


Joined: 3/18/2009
Posts: 2230

The LCD fuse should be hot all the time. It keeps the processor memory alive in the cluster. It should only have around 18-22 milliamp draw on it, key off.
One thing...never use a test light to check any of the circuits on the cluster...use a good multimeter. A test light can give false info, as well as damage some sensitive circuitry in the processor. Checking the fuse with a light is ok, but it will not show the exact voltage going thru the fuse. The test light will light up with 8volts, so you'll assume the fuse is good, but the system will not work properly with less than 12 volts.
I have a good article on finding battery drain issues somewhere. I'll see if I can locate, and post it. It may be at the shop....


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Re: Electrical Short (5/5)
 7/16/12 12:27pm
jonneyone
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galion, OH - USA

Vette(s):
1984 base coupe 17,000 miles all original. very low production number.red on red 3853. pro num.


Joined: 5/31/2012
Posts: 413

can you take a test light and go inbetween the negitive battery post and the negitive cable. if the light is on then you have an battery draw. pull each fuse one at a time when the light goes off you know what cir...it's comeing from. then check for opptions like clock , lights among other things.  this is only my oppinion

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