Saturday, January 31, 2009

Electrical Madness, The End!

I borrowed a voltmeter capable of handling up to 10A from a friend and did a little more investigating with still confusing results.

I also borrowed a trickle-charger from another friend and started recharging the battery. I figured maybe with a charged battery most of the car would be working and I could get a better idea of what wasn't. After a good six hours of charging, I turned the key, and everything works fine!

The engine started, the dash and radio work, the wipers and headlights work, even the power side mirrors and locks. No problems anywhere. Unbelievable.

What a crazy adventure! It hit some pretty low points:
- I thought I had killed my battery, and would have to buy a new one. ($80)
- The electrical system seemed hopelessly messed up. I was worried the "Body Control Module", basically the CPU for a lot of the cars electrical functions, was busted. ($200)

But in the end, I didn't have to spend a dollar to get the car running, and I learned some great lessons along the way.
- I learned about the car's electrical system and its fuses and relays.
- I learned how to diagnose a battery drain.
- I got some good practice with a voltmeter. It's pretty easy for the probe tips to make a poor connection, resulting in bad readings, so always measure more than once!
- I learned to always disconnect the battery when doing electrical work.
- I learned to always recharge the battery (if it's dead) before trying to diagnose an electrical problem.

So what went so wrong, and why did the electrical system seem so screwed up? I'm still not sure. The car hadn't been driven in at least a month when I did the work, so maybe the battery was low and got further drained as I ran the window motor up and down. I'm thinking that when the battery got too low, the electrical systems got confused, and perhaps some relays became stuck open, causing the battery drain. Maybe the voltage was even too low for the relays to properly close.

At any rate, the Trans Am's back up and running! I'm hoping to get a post up of the car soon, maybe a little clip of the exhaust to start with :).

Thursday, January 29, 2009

2007 CR-V

Well, since I won't have time to work on the Trans Am again until this weekend, I figured I'd throw up some pictures of our CR-V.

We bought it last year in anticipation of our little boy. I took these photos last year during the Zaca fire.

The CR-V's been great. It's got more than enough luggage space, and it drives like a car rather than an SUV, which is nice on the tight streets of downtown Santa Barbara. My one complaint is the 'premium' sound system--it's garbage. Both our Grand Am and Trans Am have the premium "Monsoon" system from GM and it's much better.

Hopefully you won't see me working on this car anytime soon! ;)

Saturday, January 24, 2009

Electrical Madness, Part 3

Well, searching for the cause of the battery drain didn't go so great.

I propped up the test light on the battery and started pulling fuses to see if any would make the light go out. Right away I found three different fuses that seemed to be affecting the current drain. With all three of them removed, the current drain was low enough for my pocket multimeter to read about 140mA draining from the battery. Even with three components out of the loop, that's still a big drain!

I was really hoping to find just a single fuse that would make all the difference and point to a specific component, but instead I've got three different components that are either all faulty, or pointing to a more systemic problem with the car.

I think the next step is to look into those three components a little more (one of them was the "Body Control Module", still need to figure out what that means...), and maybe get some help on a forum.

Wish me luck!

Thursday, January 22, 2009

Electrical Madness, Part 2

Well, I couldn't wait till the weekend to look into this problem, it was just too frightening.

I went out Thursday morning and checked some of the fuses. The car has three fuse centers: two in the engine compartment and one inside the car on the driver's side.

The covers for the fuse boxes have a little info on what each fuse is for, but the user manual had complete explanations (though half the things there were fuses for I don't understand. What's HVAC and what's the Body Control Module??).

I pulled a few fuses that I thought might be related to my problem. I checked the fuse for the window motors first, since that's where I've been working. Then I checked some of the ones for the instrument panel, and also the starter since the car wasn't starting. I didn't check every single fuse, but all of the ones I looked at were fine.

Feeling rather discouraged, I got in the car and put the keys in to see what would happen. I turned the key to on, and the dashboard lit up but was acting a little funny. Some of the lights on it were flickering. Trying to start the car again produced absolutely nothing.

Then I noticed that If I stepped on the break, the lights on the dash would dim. That made me suspect that maybe my battery was just dead. I got my trusty voltmeter out and measured the battery, and it read 6.7V! A healthy batter is over 12V, so that's pretty dead.

Later at lunch I was talking to a friend about my troubles, and he was getting me worried. A battery that's discharged that much may not be rechargeable... I may have damaged it and need a new one. That would suck, I could definitely think of better ways to spend $80 than buying a new battery.

He suggested that I could try taking it to a Sears auto center and that they would recharge and test it for me. So that evening I went out to remove the battery, and tested it one more time. I must have been putting the probes in the wrong spot, because now it was reading 11.4V! That still qualifies as dead according to this chart:

Battery Voltage and State of Charge:

12.68v . . . . . . . . . . 100%
12.45v . . . . . . . . . . 75%
12.24v . . . . . . . . . . 50%
12.06v . . . . . . . . . . 25%
11.89v . . . . . . . . . . 0%

But at least it's not six and a half volts dead!

I read a good article on checking for parasitic drains on the battery. Since the batteries dead, it's possible that something I did damaged a circuit or relay in such a way that it's using electricity even when the car is off.

To check for drains like this, I learned you disconnect the negative (black) terminal of the battery, and connect your multimeter in between the cable and the negative terminal of your battery, then set it measure current. Unfortunately, my little pocket multimeter has a 200mA limit, and it just played a tone as soon as I connected it, meaning the current is greater than 200mA.

I also have a test light that I used. It lit up when I connected it, but I don't know how much current it takes to light it, so I'm not sure how much help that is.

Anyway, an acceptable drain is about 50mA, so if it's more than 200mA I've definitely got a problem.

So how do I investigate it? The article says you just pull fuses one by one and watch the current reading to see which fuse causes the current to drop.

Of course, I have a problem here now in that my multimeter can't handle the current...

Wednesday, January 21, 2009

Electrical Madness

This should really be part 3 of a saga about replacing my window motor, but I can't help but talk about the problem I'm having now. I'll come back to parts 1 and 2 later.

So, early in 2008, the driver-side window motor in my Trans Am died. I endeavored to replace it myself... what an adventure! I replaced the motor only to find out that I've either reassembled it incorrectly or bent some key piece, because the window's basically jammed. But wait, it gets better...

This past weekend I took another look at the door to see if I could get the window working. The first step in the repair manual is to disconnect the battery, since you have to disconnect some wires while disassembling the door. I didn't do that this time, though, because I wanted to run the window motor with the door taken apart so that I could maybe see where it was jamming.

It was going great until some point the car went a little crazy. If I remember correctly, the seatbelt light on the dash was blinking really fast, and the chime was going off really quickly.

I put the door back together and put the key in the ignition. That's when things got sad for Chris. The interior lights came on, but the dash only lit up temporarily, and some random chimes went off. When I turned the ignition all the way on I got absolutely nothing--the starter wasn't turning and I didn't here that little clicking sound that you would still here if the starter were dead.

This is where panic set in. "Oh crap, I've destroyed my car. I must have fried every stinking circuit in the car. It's never going to run again." Well, take it easy Chris. This is why circuits have fuses. If I shorted something, a fuse should have blown and protected the circuits from damage.

I ran out of time to look into it. Next weekend, I'm planning on checking the fuses. Not sure which ones to look at, guess I'll just pull them all out one at a time and check them. I'll let you know what I find out!

The Garage

Here's my oh-so-humble workspace. Our house was built in 1928; I'm not sure if the garage is that old but it's definitely pretty ancient.

It's pretty much a wood shack best suited for the set of a horror movie. Scared? No? Well, what if we... tilt the camera!!!

Anyway, there are clearly some cleanliness / junk issues here. It is at least a pretty wide garage, with plenty of space on either side of the car.

The door isn't automatic or even on rollers, it's got these huge springs that help you lift it. When we first moved in, I figured the door was broken because I couldn't get it open. Turns out it just needs some muscle and some finesse to get it over a lip in the pavement of our uneven driveway.


Welcome to my auto blog. I'm using this blog to talk about what I'm doing with our cars--repair, maintenance, maybe some "mods"?

Here are the cars that we currently own and that I'll be working on:
  • 2000 Pontiac Grand Am (My daily driver)
  • 2007 Honda CRV (Our grocery getter and baby toter)
  • 2002 Pontiac Trans Am WS6 (My baby)
I wasn't brought up working on cars--I didn't help my dad restore a '69 Camaro, and I didn't have friends in high school who called me over on weekends to help work on their cars. So I'm a definite amature here. I love cars, though, and I love working on them, so when I do something with our cars I wade into deep waters hoping that my interest in the work will keep me afloat.

That said, any kind of auto work I accomplish here you can be confident you could do, too.