MustangSally99

Cheese and rice!!! The Ford dealer who recently worked on my '99 GT said there was less than 20 milliamp draw on the electrical system (after replacing the amp). The local mechanic (who also races at the same track as me for 20 years) says there is 187 milliamp draw. I call the Ford dealer, and he insists the test was correct, and this other mechanic doesn't know what he's doing, maybe reading on the wrong scale.

Ford Guy says 187 milliamps would drain the battery overnight. I haven't had any problems letting her sit for a few days and still starting.

Local Mechanic says he knows what he's doing, and there IS a large draw on the battery. He worked on this car a few years ago, and we didn't trace the draw then, I simply disconnected the battery cable when I wasn't driving her.

Ford Guy says the battery cables (negative in particular) are severely corroded from resistance, and that the alternator could be the cause, since the connection there has burned the plastic and the corrosion is worst at the alternator.

Local Mechanic says there isn't any obvious corrosion, and he tested the cables and found no resistance. (He replaced the wires a few years ago, right after I replaced the alternator.)

*GRRRRRR*

So I asked Local Mechanic to spend half an hour and test the big stuff, like the alternator, to see if they can find the draw. If he can't locate the parasitic drain, what then????

I'm going crazy!!! I just want this car to be mechanically sound when I sell it, but I don't want to dump a ton of money in her.

tncruiser

how long does it sit before the battery goes dead?

Colorado_Mustang

Checking the drain is about the easiest thing you can do. Insert ammeter between negative battery post and its cable (disconnected cable, of course).

Then, remove fuses one by one until the current draw goes down. You found the problem.

MustangSally99

Last time the battery went dead was when it was at the Ford dealer two weeks ago, and they let it sit for 4 days...and it was dead.

I asked Local Mechanic to see if he could find the culprit, and he said its coming from the amplifier fuse, which also runs the radio, CD player and just about every light inside the car. I think he said he checked the 'master fuse', so I guess that means there are individual fuses for each of these functions. He said it could take hours to trace it, at $90/hour.

A meter costs $10, and it might take me a whole afternoon. Is this something I could do myself? I've been under the hood since I was 16...many many moons ago, so I think I could learn how to do it.

Thanks for the responses, guys!

[IMG]local://upfiles/9569/CE66E9DB3FA645FF889C1DDD2DAEF009.jpg[/IMG]

MustangSally99

So it's the "F" fuse, position is I/P (don't know what that means) and circuits protected are Instrument Cluster and PCM (Power control module?) not sure what that is either.

The question remains, what fuses under the dash are contected to this fuse?

MustangSally99

Talkin' to myself now...

I'm testing the electrical drain by letting the car sit for a few days and using the instrument cluster diagnostics.

Saturday was the last time I drove her. No problems.
Tuesday I checked the battery voltage by using the gage on the dash and the diagnostics. The dash gage needle was right in the middle, and the diagnositcs gave me a code of 148.
Thursday I checked again...gage needle was in the same place, but the code is 145 now.

So I definately have a drain. It may take another 7-10 days to really know how much and how fast.

I'll keep this thread going in the hopes that I come to some conclusion, andhopefully will help someone else with a similar problem

MustangSally99

So here are the numbers from the instrument cluster diagnostics over 7 days:

Tuesday 148
Thursday 145
Friday 144
Saturday 147

Drove her on Saturday.

Sunday 155

My conclusion: there is no significant parasitic draw on this car. The high reading the Local Mechanic got must have been when the computer 'woke up' and was checking stuff. And maybe if she sat for 4-8 weeks there may be a problem starting, but I don't consider that to be a major concern.

Problem solved

Gary H

Have you checked things like the trunk light, underhood light and cig lighter to see if they are staying on?