elctrical short

sugadoc · #1 (**permalink**) 05-25-2003, 09:17 PM

I have a 1984 spider which keeps running down the battery when it sits for 2 or more days. I have isolated it to the 5th circuit breaker (radio, turn signals, clock, and ignition light and key buzzer. I think the problem is related to the key buzzer and ignition light, any suggestions?. Does anyone know where the buzzer is located. Also does anyone have a wiring diagram for this car?

**Roadtrip** · #2 (**permalink**) 05-25-2003, 09:22 PM

Check the back of your owner's manual. Alfa usually has a wiring diagram there . . . . . at least the 70s models do.

sugadoc · #3 (**permalink**) 05-26-2003, 08:27 AM

No owners manual, I bought this car thirdhand

**Roadtrip** · #4 (**permalink**) 05-26-2003, 09:12 AM

I don't know specifically about '84 models, since my 74 was made before the advent of ignition switch lights and key buzzers. But, on '70's models the turn signal flasher is between the fuseblock and the steering column and I wouldn't be surprised to find the key buzzer somewhere close to there. It's pretty tight up in that area so you may have to remove the two screws that secure the fuseblock out and move the fuseblock down to get a better view. Obviously, disconnect the battery before you do that.

If you don't have a service manual for your car, you should get one. IAP, Centerline, etc all have them. The CarDisc is good as well. They're also available on Ebay pretty regularly.

I don't know about you, but the first thing that happens when I buy a car is to remove that key buzzer.

73Alfa2000 · #5 (**permalink**) 06-04-2003, 08:05 AM

Just wondering how you found out that it was at the 5th circuit breaker? I have the same problem on my 73' spider and have been told it was a bad ground somewhere. I dont know where to start.

**Roadtrip** · #6 (**permalink**) 06-04-2003, 08:36 AM

A bad ground won't cause a drain on the battery. I'll cause erratic or no function of it's associated equipment.

It's best to troubleshoot an electrical problem with an sensitive ampmeter. With the key switch off, remove all the fuses and test for current across the contacts. Unless you have a piece of equipment like a clock that is on a hot bus, you shouldn't have any drain. This way you can isolate the drain to a certain circuit. From there you can isolate it to a particular item.

You can also connect the ampmeter to the battery and remove fuses one at a time until the meter reads zero.

On an 86, you have a computer for the FI system. I think that draws a tiny amount of current to keep the volitile memory alive, but I'm not sure.

sugadoc · #7 (**permalink**) 06-04-2003, 05:47 PM

I found out it was the 5th fuse by using the multimeter and showing that there was a current thru the circuit even with the car off. This circuit contains the radio and turn signals and ignition and ceiling lights so it should have power when the ignition key is off. However when I remove the fuse and do not use the car the battery does not drain down.

If there is a short to ground and the current is on, then the battery will run down.

73Alfa2000 · #8 (**permalink**) 06-05-2003, 08:06 AM

I went and bought a multimeter from radio shack and will give it a try. when I find the circuit I take it I have to trace all wires and ???. Look for a fray/break? Do I need to look just at the grounds coming off that circuit?

**Roadtrip** · #9 (**permalink**) 06-11-2003, 03:18 PM

A bad/dirty/loose GROUND Wire will not cause current loss. It will likely result in erratic operation of the item it's associated with, because the circuit is not being completed continually.

A hot wire that has a break in the insulation and is touching a ground (car body, sheet metal, etc.) will allow a freeflow of current and loss of battery power. In addition it can be a fire hazard because of the possible heat generated. In essence, with the high amount of current passing through the wire, it starts to act like a heating element.

73Alfa2000 · #10 (**permalink**) 06-24-2003, 07:58 AM

Used the multimeter on the battery and it registered 12.46. Didnt know if that was supposed to do that so I put it on my truck and it registered the same. Since my battery will not hold a charge I suspecting that the battery is bad. And not a short.

Sound right?

**Roadtrip** · #11 (**permalink**) 06-24-2003, 11:44 AM

Use a hydrometer and check each cell in the battery. If you find one that grossly different than the others, that's a good indication that the battery is bad . . . . . or just take it up to a shop and let them test it.

73Alfa2000 · #12 (**permalink**) 06-24-2003, 12:00 PM

Sounds Good to me.............Thanks John.

Keven · #13 (**permalink**) 07-03-2003, 09:01 AM

My mother in law's BMW was expereiencing the same
problem, and it turned out to be the ignition switch.
But it only drained the battery when the key
was in the ignition. So if she pulled the key
out, no current draw. She keeps the keys in
cause the car is parked in a locked garage.
Poor thing has to pull the keys out now and drag
them inside.

Have you tried measuring the current with the
key in, and also out?
Just a thought.

alfabill · #14 (**permalink**) 07-13-2003, 07:40 PM

many years of professional auto repair have taught me some things that novice alfa owners should abide by...
1. perform an in depth battery performance test. test battery load,check water level, check variences in cell readings, and above all check charging rates. a common rule of thumb states that if a battery requires more than 15.5 volts to charge the battery should be replaced. i have brought back a few batteries but not enough to call it a fix. before any other determination of an electrical system problem can be diagnosed a good battery must be present.
2. perform an in depth diagnosis of the charging system, including load testing to alternator maximum output, diode integrity(shorts). a screw driver held near the armature while running is'nt good enough.
after these two items are put in order the a problem, if it still exists, can be diagnosed.
electrical draws are measured in milli-amps. usually thirty or less is normal. pulling a clock fuse and watching a voltmeter is inaccurate at best and anyone who says different simply does'nt know what they are talking about.
ALWAYS take care of basics first. this will cure seventy percent of all electrical gremlins. for the rest of you, clean all connections and grounding points and continue with the diagnoses. alfabill