TheSamba.com :: View topic - Interior light ground and fuse. (and phantom draw)

Tue Apr 24, 2012 4:12 am

I had a bad short where my alternator cable was rubbing on my transmission.
Now my westy 3 bulb interior light does not work.
Also, the driver door light comes on in the “door” position, but not the “on” position.
I have a feeling these two are related.

Can someone tell me where to look for the ground on these two?

Thanks

Tue Apr 24, 2012 4:51 am

The 1987 driver light is shown on diagram page 97.110, as INTERIOR LITE, FRONT. Pin 31 is always the ground connection, a brown wire. Follow the brown wire down to the bottom of the page where it is labeled with a circle with a number inside. Look at page 97.103 for the list of ground circles with numbers inside and a location where each is to be found.

Mark

Zero419 wrote: I had a bad short where my alternator cable was rubbing on my transmission.
Now my westy 3 bulb interior light does not work.
Also, the driver door light comes on in the “door” position, but not the “on” position.
I have a feeling these two are related.

Can someone tell me where to look for the ground on these two?

Thanks

Tue Apr 24, 2012 4:59 am

Zero419 wrote: I had a bad short where my alternator cable was rubbing on my transmission.
Now my westy 3 bulb interior light does not work.
Also, the driver door light comes on in the “door” position, but not the “on” position.
I have a feeling these two are related.

Can someone tell me where to look for the ground on these two?

Thanks

The lights and door switches are all poorly made and known for giving problems. Both respond to being cleaned, but sometimes just need to be replace.

Tue Apr 24, 2012 9:43 am

What is the trick for hinting down a battery draw?
I know I should pull fuses until I see the voltage stop drawing, but where do I hook up the VOM? disconnect the negative battery cable and hook the VOM in series?

Tue Apr 24, 2012 9:46 am

Zero419 wrote: What is the trick for hinting down a battery draw?
I know I should pull fuses until I see the voltage stop drawing, but where do I hook up the VOM? disconnect the negative battery cable and hook the VOM in series?

I hook it in series and use the volt setting, others prefer to use the amps setting, but it is easier to burn up a meter that way.

Thu Apr 26, 2012 8:27 am

I have a very cheap VOM
So I picked up one of these on amazon...

It will be here on May 5th....

Thu Apr 26, 2012 10:01 am

That'll do! :wink:

Good luck hunting...

Fri Apr 27, 2012 3:26 pm

Talked to the guys at Bostig and they gave me a good idea how to track it down. I pulled the fuses one by one, using my old VOM between the neg. battery and saw no drop. Went for a 12 mile ride (the motor was great).
the battery got hot, the alternator was hot, and a little bit of water/acid came out of the battery overflow. there is a spark when I try to attach/detach the negative cable. The guys at bostig say this all points to a huge draw, possible short to ground.
So I need to pull the cable off of the starter and check for voltage drop, check the grounds, check the voltage at the battery and at the alternator while running to make sure there is lee then 1v difference. try to start narrowing it down.
I might get some time tomorrow to start.

Sat Apr 28, 2012 1:46 am

You may well have toasted the diodes in your alternator. Assuming you can get at it remove the cable from the back of the alternator and see if your ground goes away.

Sat Apr 28, 2012 5:41 am

That's what I was thinking.
My lights on my dash have never been brighter and I measured about 15v.

Got my boys first T-ball practice today so maybe I can check it out after nap time.

Sat Apr 28, 2012 9:23 am

T-ball was great!

I pulled the alternator wires, that didn't do it.
I pulled the two spade connectors on the started, nope.
I pulled the big lug off the starter, nope.

I'm at a loss.

Sat Apr 28, 2012 10:05 am

Didn't do what? What exactly are you watching for?

Not voltage I hope.

Mark

Zero419 wrote: T-ball was great!

I pulled the alternator wires, that didn't do it.
I pulled the two spade connectors on the started, nope.
I pulled the big lug off the starter, nope.

I'm at a loss.

Sat Apr 28, 2012 10:57 am

Your ignition switch isn't fused and gets it's power straight from the battery. Try removing the plug from the switch and see if that kills your draw.

Sat Apr 28, 2012 11:05 am

How many amps is the draw you are trying to find?

There should be only 3 or 4 wires to the battery plus terminal. Take them all off. Then connect them one at a time while measuring the current draw. Once you know which major path the draw is on then you can try to find it by looking at the things on that path alone. The shotgun approach works for trivial cases. Difficult cases can take a more reasoned approach to succeed.

Mark

Zero419 wrote: T-ball was great!

I pulled the alternator wires, that didn't do it.
I pulled the two spade connectors on the started, nope.
I pulled the big lug off the starter, nope.

I'm at a loss. [/quote]

Sat Apr 28, 2012 1:32 pm

New meter came today.
Not sure how to use it.
With it set on m (I assume micro, not milli) I am searching for a 5.6 micro amp draw, I think.

It may be related to my westy camping light. The bulbs are fine, and it went out while I had that short with the old alternator wire contacting the transmission body.

I cant find my Bently right now, and honestly don't have much time to find it.

When I do find more time, I am going to take Jim's advice from bostig and start a notebook of my different findings.

I removed the two fuses from the small box behind the drivers seat. I pulled all the wires under the drivers seat.

Not sure what else feeds the light or grounds it, Like I said, I'll have to find my Bently

Sat Apr 28, 2012 2:00 pm

If all you have is 5 microamps or even 5 milliamps you don't have a draw worth worrying about.

Sat Apr 28, 2012 2:06 pm

I'll have to start reconnecting things and see what pops up.

Sat Apr 28, 2012 2:41 pm

If the meter just came today what exactly were you using to check things before? How were you doing it?

A draw of 5 milliamps or even 50 milliamps isn't the cause of the problem at this point in your project. You might want to put everything back and start over. Make sure you actually have a serious amp draw before you then try to track it down.

Mark

Zero419 wrote: New meter came today.
Not sure how to use it.
With it set on m (I assume micro, not milli) I am searching for a 5.6 micro amp draw, I think.....................

Sat Apr 28, 2012 3:34 pm

An older cheap VOM that (apparently now) does not work.
Every time I measured current the needle pegged.

I will be putting everything back and checking it out.

Not now. kids are at grandpa's. Party time now.

Sat Apr 28, 2012 4:15 pm

Zero419 wrote: An older cheap VOM that (apparently now) does not work.
Every time I measured current the needle pegged.

I will be putting everything back and checking it out.

Not now. kids are at grandpa's. Party time now.

That is why it used to be normal practice to use the voltage scale and not the amperage scale. Start out with a scale that will safely read 12V and then if the voltage was towards the bottom of that scale, you would switch to a lower voltage scale.