Corvetteforum: Electrical draw driving me CRAZY (Read Only Topic)

Corellian Corvette
Senior Member

1046 posts [100%]
Kirkland WA

Electrical draw driving me CRAZY

10:57 PM 3/8/2002

OK -- this one has me seriously stumped.

I've killed two batteries in the last month trying to find this electical draw.

The procedure that I've read here is to unhook the negative battery cable, attach a test light between the neg. cable and the neg. terminal, then pull all the fuses until the light goes out (making sure the door ajar and courtesy lamp pins are in).

Well, right now I have *every* fuse out of the fuse box, both doors are closed, and the test light is STILL on.

The only time the light did anything is when I pulled the clock/lighter fuse, then the lighted "dimmed" but didn't go off.

It makes sense that the light would dim w/o the clock fuse because the clock is supposed to have power with the engine off. Still, the test light stays on even with every fuse removed.

So -- can any electical gurus tell me what the next step here is? Is there any other way to test for a draw?

Thanks - please help I can't afford any more batteries!!

[Modified by Corellian Corvette, 12:57 AM 3/9/2002]
_______

1999 "Corellian Corvette"
Outside: M6. Z51. Halltech TRIC w/ Cobra CF. Aluminum MAF. Carbon fiber rail covers. CAGS bypass.
Cool Blue upgrade. Corsa "Pace Car" (New Tips) w/ X-Pipe. Y2K Painted Rims. Firehawk RFT's.
Inside: Valentine 1. In-Dash CD w/ 12 CD changer. Custom Lloyd Mats.
Dynoed: 323 HP / 337 TQ (before Halltech and Exhaust)

1973 Stingray
Silver/Black. 350ci L48. TH400 Auto. Aluminum Wheels. Kenwood stereo w/ CD Changer. Power Antenna.
Edelbrock Performer intake. No emissions. 1.60 roller-tip rockers. 2.5in duals w/ Flowmaster mufflers.

ME
MY WEBSITE
THE CORELLIAN CORVETTE
"...she'll do .5 past light speed!"

kenincanada
Senior Member

158 posts [100%]
Victoria B.C.

Re: Electrical draw driving me CRAZY (Corellian Corvette)

11:58 PM 3/8/2002

What year? Some altanators with builtin regulaters can cause a drain [faulty reg.] or exturnal regs. you would hear it click when you remove the batt. cable
_______

1977 L48 STOCK

Corellian Corvette
Senior Member

1046 posts [100%]
Kirkland WA

Re: Electrical draw driving me CRAZY (kenincanada)

12:00 AM 3/9/2002

It's a '73. The alternator is new -- just replaced because my old one was bad.

Thanks!
_______

ME
MY WEBSITE
THE CORELLIAN CORVETTE
"...she'll do .5 past light speed!"

kenincanada
Senior Member

158 posts [100%]
Victoria B.C.

Re: Electrical draw driving me CRAZY (Corellian Corvette)

12:07 AM 3/9/2002

does the 73 have a builtin reg. I cant remember ? even new could still be a problem. Did you try unplugging the alt.?
_______

1977 L48 STOCK

Chris70
Senior Member

28 posts [100%]
Stolberg, Germany

Re: Electrical draw driving me CRAZY (kenincanada)

3:24 AM 3/9/2002

This is me!

I killed 2 batteries - they got completely drained while the car was sitting in the garage over the course of a few weeks max. I cured the symptom via a switch at the battery terminal. I hear a "click" everytime I connect the battery - sounds like a relay.

Thanks for the alternator idea - will test this when the weather gets better.

Chris

_______

1970 Convertible 350/300

mrvette
Senior Member

1298 posts [100%]
Orange Park Florida

Re: Electrical draw driving me CRAZY (Corellian Corvette)

5:13 AM 3/9/2002

The electrical system in a car is really quite simple, bitch to get to, but simple just the same.....
so first thing is, pull the connector to the horn relay, the black/green wired thing under that terminal block on the driver's side fender liner, under the outer fender....the one that looks like the distribution power block, it's a dual funchion unit...distrib and horn relay...dumb idea really...
what may be is the horns are bad, and the horn button circuit is drawing current closing relay but horns don't blow....
another thing is the alternator, pull the power output wires, and the 2 pin connector....does light change significantly???
another spot is the starter, where the large battery cable is connected there is another wire there, goes to the electrical circuit...and maybe two small wires, for solenoid controll and ignition....
if the car cranks ok, the 2 small wires are correct....
NOW there is also a large loop end black heavy wire, that goes to ground, engine block, NOT the battery positive at solenoid....common mistake when changing starter....among other things this grounds the heater motor frame and the wiper motor assy.....
pull/test these wires and lemme know what you find...individual email is best as I may not check this post again...depends....
you may also check the brake lights, make sure the pedal switch is adjusted right....
you may also unplug the rear wiring harness by the connector up under the driver's kick panel...rectangular connector, about 6-8 pins per side...maybe a dozen wires in all....
you could unplug the flasher/turn signal wires also...that long flat connector under the steering wheel....

since the fuses are pulled, and the drain is still there, the latter suggestions make NO sense in a stock wired car, but someone in 30 some years may have gronked the system.....hard to say....

GENE
_______

http://home.att.net/~ncmpics/mrvette.htm

dman535
Senior Member

231 posts [100%]
Waterford, MI

Re: Electrical draw driving me CRAZY (mrvette)

9:53 AM 3/9/2002

Instead of using a test light, use an ameter to measure your current draw. It will be much more accurate than a test light. Most lower-cost multi-testers will allow up to 10 amps of current measurement.

_______

Derek A.
1977-L82-700R4

http://www.corvetteforum.net/c3/dman535/

jackson
Senior Member

40 posts [100%]
Florence SC

Re: Electrical draw driving me CRAZY (Corellian Corvette)

12:12 PM 3/9/2002

The alternator posts may be pointing in right direction. I'm NOT an electrical etch but I've heard this same thing before ... and I've heard it can be cured by putting an external Radio Shack diode inline with one of the alternator wires. Acts like a one-way gate for current flow. I've never done it ... but would like to know the details. Maybe some of the elec techs can chime in here on the diode trick?

More info: A diode (1A-100V) goes inline with the smallest alternator wire (usually brown).

[Modified by jackson, 4:26 PM 3/9/2002]

Corellian Corvette
Senior Member

1046 posts [100%]
Kirkland WA

Re: Electrical draw driving me CRAZY (jackson)

12:28 PM 3/9/2002

Man -- this sounds like it's going to be a lot of work.

OK, so using an ammeter, what should I be testing for and how do I do it? Do I test the terminals at the battery or someplace else?

Is there an acceptible amount of draw? What parts should be getting power?
_______

ME
MY WEBSITE
THE CORELLIAN CORVETTE
"...she'll do .5 past light speed!"

Corellian Corvette
Senior Member

1046 posts [100%]
Kirkland WA

Re: Electrical draw driving me CRAZY (Corellian Corvette)

1:06 PM 3/9/2002

UPDATE!

Ok, I found out what was keeping the light on -- it's the two lead wires going into the top of the alternator (the Brown and Black ones). When I took those off the light died.

I have the brown wired going into the right terminal, and the black one in the left terminal.

Does that mean anything? What are my next steps here? The alternator is new (about 2 months old).

Thanks!
_______

ME
MY WEBSITE
THE CORELLIAN CORVETTE
"...she'll do .5 past light speed!"

Black68Vette
Senior Member

223 posts [100%]
Lutz FL

Re: Electrical draw driving me CRAZY (Corellian Corvette)

1:10 PM 3/9/2002

I'd say its time to bring the alternator back to where you got it

_______

Oh my god, what was I thinking

with a 68? Well, she's my baby now... Guess I'm gonna make the best of it, just like marriage, till death do us part

RoyArms
Senior Member

126 posts [100%]
Gulfport FL

Re: Electrical draw driving me CRAZY (Corellian Corvette)

1:10 PM 3/9/2002

did you check to make sure the alarm system is off? I had a similar problem and it was the alarm system drawing current. The horn was rusted solid so it want making any noise. But when you say you connect the battery and hear a click, that could most likely be the click of the alarm relay. I heard the same click. Is the click comming from around the shifter area? Because that is where the alarm relay is... hope this helps...
_______

1978 Pace Car

350 chevy crate motor (dunno, thats what came in it)

paso
Senior Member

869 posts [100%]
Saskatoon Saskatchewan Canada

Re: Electrical draw driving me CRAZY (Corellian Corvette)

1:11 PM 3/9/2002

Okay now this is getting interesting

All the above answers we're real good I thought for sure it was in the horn relay or alt. Now lets look at what has power all the time not fused...... tic tic.... Factory alarm switch on fender?? neatral safety switch in counsel..... solenoid.... You did remove batt cable at alternator.... not just the plastic plug... dam I'll sleep worse than you tonight.

_______

http://vettefinders.com/77registry/

Corellian Corvette
Senior Member

1046 posts [100%]
Kirkland WA

Re: Electrical draw driving me CRAZY (paso)

1:23 PM 3/9/2002

Yeah this is interesting!

OK, I have now put everything back together with the exception of the clock fuse and the two wires on top of the alternator.

The light is still off.

I don't here a click when I put the battery on. The Alarm system was repaired but I haven't used it in about a year. I'm not ruling that out as a possibility.

Since I know there is supposed to be power to the clock, I'm not surprised about that.

Now, If I want to take the Alarm system out of the equation, where would I disconnect it to see if it's the cause of the draw?

[Modified by Corellian Corvette, 3:25 PM 3/9/2002]
_______

ME
MY WEBSITE
THE CORELLIAN CORVETTE
"...she'll do .5 past light speed!"

jackson
Senior Member

40 posts [100%]
Florence SC

Re: Electrical draw driving me CRAZY (Corellian Corvette)

1:35 PM 3/9/2002

More info: A diode (1A-100V) goes inline with the smallest alternator wire (usually brown).

The 73 came with an internal regulator (which has its own diode that may've failed). You changed alt about 2 months back ... since have had battery probs.

Best bet: exchange the alternator

Corellian Corvette
Senior Member

1046 posts [100%]
Kirkland WA

Re: Electrical draw driving me CRAZY (jackson)

1:53 PM 3/9/2002

I certainly don't rule out the alternator as a problem, but I was having this draw before hence why I replaced it. So, It's possible they both have the problem.

When I return the alternator what do I tell them? I know they can test so what are they testing for?

Thanks!
_______

ME
MY WEBSITE
THE CORELLIAN CORVETTE
"...she'll do .5 past light speed!"

jackson
Senior Member

40 posts [100%]
Florence SC

Re: Electrical draw driving me CRAZY (Corellian Corvette)

2:50 PM 3/9/2002

If you had this prob before alt R&R then may not be alt ...but still could be because your old alt may've had same prob. Fresh ones can too. But, it's not so difficult to remove alt ... take it back ... tell them you suspect internal reg is bad. After only 2 months, they'll probably give you another. If it doesn't solve the problem then you're not out so much time trouble. Just trying to help.

Corellian Corvette
Senior Member

1046 posts [100%]
Kirkland WA

Re: Electrical draw driving me CRAZY (jackson)

2:54 PM 3/9/2002

Good point. I'll try that this afternoon.

Also, I removed the wires from the Alarm relay in the rear compartment. Light still stays on with the alternator connected. So, doubtful it's the alarm unless that's not the right place to disconnect.

Thanks!
_______

ME
MY WEBSITE
THE CORELLIAN CORVETTE
"...she'll do .5 past light speed!"

Corellian Corvette
Senior Member

1046 posts [100%]
Kirkland WA

Re: Electrical draw driving me CRAZY (Corellian Corvette)

4:37 PM 3/9/2002

Sorry to keep posting on this.

I just replaced the Alternator. Same problem - as soon as I plug the sensing wires in the top the light goes on. Even if the rest of the alternator is unhooked.

Now I'm really stumped here.

MrVette suggested that I might have the wires crossed. Does anyone have a good diagram?

Right now I have the BLACK wire connected to the counter clockwise pin closest to the fender (which I believe is the POSITIVE lead), and the negative lead (closer to the engine block) has the BROWN wire attached.

Still, all my other gauges and everything seem to work fine.

What would happen if I reversed them? Would a draw be the only problem?

Is there a good wiring diagram to look at?

Thanks again!!

_______

ME
MY WEBSITE
THE CORELLIAN CORVETTE
"...she'll do .5 past light speed!"

2ND77
Senior Member

138 posts [100%]
Beacon Falls CT

Re: Electrical draw driving me CRAZY (Corellian Corvette)

5:25 PM 3/9/2002

I would not recommend reversing those wires without a drawing. You could damage the alternator. My guess...since this is the third alt. is that something in line with one or both of those wires is shorting...but its the alt. that is making the circuit good when its connected. Follow the wires back and look for bare spots or anywhere it may be touching metal. This may take some effort..depending on how well they are loomed or where they go, but I think I would do that. I have found many shorts in car wiring that way.....gremlins chew the insulation and such. I think you can safely rule out the alt at this point. My guess....the wires them selves. Just my 2 cents.

Ron
_______

Go Navy!!

Corellian Corvette
Senior Member

1046 posts [100%]
Kirkland WA

Re: Electrical draw driving me CRAZY (2ND77)

5:40 PM 3/9/2002

PROBLEM SOLVED!

I had the wires crossed this whole time. Re-checked the wiring diagram (with some help from mrvette) and it seemed to be backwards. Switched the leads, the light doesn't go on. Turned the crank, the car fired up and everything appears to be working OK. No sparks or burned fuses.

Turned everything on (radio, lights, heater) and it's working as well.

I'll know in a few days if the battery dies again if this was the problem.

I want to send out special thanks to Gene (mrvette) for helping me through via email, and thanks to you guys for posting.

Barry's70LT1
Senior Member

319 posts [100%]
Halifax NS

Re: Electrical draw driving me CRAZY (Corellian Corvette)

5:44 PM 3/9/2002

Here is a diagram from a '70. it should be the same for a '73.
Barry

_______

1970 Unrestored: 350/370, M21, 3:70, F41, PB, PW, TT, TI
Original Owner, Original Paint, 13.02 @ 110.30

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