I have a 2004 ford van with 42,000 miles. Recently it developed 2 problems.
1. The battery goes dead if it sits for a week without driving. All it has that runs continuously is a clock. That shouldn’t cause the battery to go dead in a week; I have replaced the battery twice, I don’t think it is the battery.
2. Today the brake pedal went all the way to the floor without the brakes working, this happenned twice. I had the brakes checked by my dealership, they couldn’t find anything wrong. Any ideas?
The battery is being drained by something. There are more things supplied power while the car is off than the clock. Have a shop check out the drain problem. By monitoring the current and pulling fuses you can find the problem.
The brake problem seems it would have to be with the master cylinder. I would replace it immediately.
If that is an original battery (now four years old) it may be normal drain. There is a lot more than the clock normally. You car has a number of computers that stay on and maybe radio, to keep the stations etc. In any case stop by your local auto parts store first and have them check the battery and charging system. That may find the problem. However Cougar’s suggestion is at least as likely, but it takes a little more work to find.
Not as likely, but it might even be a corroded or loose battery cable.
I also agree with Cougar on the brakes, but I will add it may also be the slave or a vacuum system problem, but less likely. I would still start by having the master replaced. This is not something you want to have happen when you are driving.
FYI…I had a shop test the draw on the battery; with engine off and key out of the ignition there is a .45 amp draw on the battery. The battery is virtually new, installed only 3 months ago. Battery posts and clamps are spotless, absolutely no corrosion.
Thanks for the assistance.
Dennis
450mA is high from what I can find out. 50-100mA is normal. Did the shop wait an hour after they turned the key off? Many circuits wait a period of time before powering themselves down to the lowest power state. Note that opening a door or doing anything to the car can reset that delay.
with 450ma and a 80 amp-hour battery (typical, check yours), the battery will be dead in 7 days.
key-off drain has nothing to do with the age of the battery, just what loads are on the battery and how they power themselves down (if they do).
Note that old batteries can have internal leakage, but that is a different matter, and difficult to measure.
Dennis, if you can’t trace down the leak, consider a cheap charger that you can plug into the cig lighter when car not in use (if you have a wall outlet nearby), about $25, or a more expensive solar cell charger.
PS how many times has the battery gone dead since you installed it? More than a few and even if you correct the leak, you will need a new battery again…
You state that the shop found a .450 amp current drain, which for a parked car is a large amount of current drain if the electrical system is in the ‘sleep’ mode. It is no wonder you are having trouble. Normal current drains should be under 80 milliamps, typically around 30 milliamps from what I have seen in the past.
It is important to know if the electrical system is going into the sleep mode. You should see a difference in current drain after the car has been shut down for a few minutes anyways. To see what area is pulling the extra current, pull out fuses one at a time and see if the current drain goes down. Pulling some and placing them back in will take the system out of the sleep mode so you need to be aware of that. Once you determine what area is causing the trouble you can check things on that circuit to pinpoint the trouble.
You have a drain on the battery.
.45 amps is too much, the spec is .050 milliamps.
Keep in mind that just opening the door can take the car out of sleep mode and cause a big jump in current. The shop checking for excessive parasitic drain should know this.
Does this van have a key pad on the door?
Have one of those switches put on the battery cable where you can use a key and disconnect the battery. You can no longer park it for a week without running it. It doesn’t just happen on Ford vans. It happens on lots of vehicles. Some last a month or two and some just hit the wall and won’t anymore. If you weren’t low on brake fluid and the rear cylinders weren’t blown out, you need a new master cylinder. It’s a classic symptom anyway.
Realize that if you do that, you will reset the radio and the computers. What effect this will have on the driving is up to the individual car. May change shift points.
I think the key-off current is much too high and indicates a fault somewhere. Cars are designed to sit unused for several weeks and startup with no problem. I know my car, an 03 with lots of computers, will sit 2 weeks no problem. The only thing that the manual says is that the blinking light that indicates the alarm is active goes off after a day to save battery. One blinking light is only a few millamps!