TheSamba.com :: View topic

Sat Feb 09, 2008 3:56 pm

So I was sitting outside the other day watching my kid roll around on a skateboard, I noticed out the corner of my eye my brake lights were on on my van.

A little odd, but OK, so I go check it out. I notice the brake pedal doesn't return enough to trip the brake light switch. I unhook both wires and unscrew the switch and have a look, it seems to be functioning fine as the switch is pushing in and out with no hangups, so I screw it back in and give it a few extra turns to make up for the slack in the brake pedal. All is good so it seems as the brake lights are only on when the pedal is depressed.

The lights had been on for a while because the lenses were fairly warm, so I go start the car to check on the status of the battery, car starts, sweet, no worries.

The following morning I go out to the car to take my kid to the beach - Car won't start, seems something sucked the juice out the battery overnight. I get a jump start and take off, it's a 30 minute drive as I took the long way so the battery gets a decent charge. We muck around at the beach for a few hours and drive home.

This morning I go out, and the car won't start. Shit..

Thinking about it, I'd say the brake switch is the culprit, seeing as things were fine up till that problem, I just don't see how it's possible it the brake lights aren't actually working?

So where do you start with this drama? I figure an auto electrician would be the best start, but you know, I like to have a fiddle before I waste someones time with a relatively simple? problem.

No lights are on
Stereo is off

Any ideas?

Mon Feb 11, 2008 9:13 am

If the brake lights aren't on, I doubt the switch is your issue. To test, pull the brake light switch out and check for continuity across the two poles. If the switch is in your hand (so no force from brake pedal closing contacts) and you can read resistance, then its shorted out internally.

Otherwise, pull one fuse at a time from the panel and check for continuity across the two fuse lugs in the block. Basically the meter (or test light) will be checking for a closed circuit. A closed circuit is taking electricity and thus draining your battery.

The problem is on modern cars, you do have several small current draws when the key is off. So things like the engine's computer, radio, dome lights, etc, will show a current draw.

Fri Feb 15, 2008 8:51 pm

Well, a good way to get an idea of where to look is this old trick:
Turn everything off in the car. everything.
Stereo, dome lights, ign, everything that can be turned off should be.
Disconnect battery NEG cable, connect a test light between the battery ground cable and the neg post on battery.
The light will LIGHT up if you have current flowing through the light.
If you have a "draw" the light will be on- start pulling fuses until (hopefully) the light goes out. If it works, and the light goes dark look at the fuse you just pulled and start troubleshooting the thing that run through that circuit.
The more modern the car the harder this test will be.
It might save you a few $ @ the electrician if it works.

Wed Feb 20, 2008 1:03 am

Could be a bum battery.

Wed Feb 20, 2008 7:19 am

Sample wrote: Could be a bum battery.

X2 How old is it?

Wed Feb 20, 2008 12:28 pm

Bub wrote: Well, a good way to get an idea of where to look is this old trick:
Turn everything off in the car. everything.
Stereo, dome lights, ign, everything that can be turned off should be.
Disconnect battery NEG cable, connect a test light between the battery ground cable and the neg post on battery.
The light will LIGHT up if you have current flowing through the light.
If you have a "draw" the light will be on- start pulling fuses until (hopefully) the light goes out. If it works, and the light goes dark look at the fuse you just pulled and start troubleshooting the thing that run through that circuit.
The more modern the car the harder this test will be.
It might save you a few $ @ the electrician if it works.

Spot on post., glad I didn't have to type it. :wink:

To clarify, the test light should never remain on in the completed circuit described above, as long as everything is tuned off.
This test shows current, there should be none with everything turned off.

Do know that on modern cars the test light will go on for a few seconds to charge up memory batteries.

If this is a Honda, dont even mess with it, take it to the dealer.

Water will make electrical problems on otherwise perfect systems.

Mon Feb 25, 2008 11:52 pm

Do you know for sure that the van will start without having your foot on the brake pedal?

I know VW had a run of bad brake light switches and they can cause more problems than you can imagine on a car with an automatic transmission.