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I have a very perplexing electrical issue.

5501 Views 23 Replies 6 Participants Last post by  Zedhead
First, let me start by saying this is by far NOT my first rodeo. 62 y/o and been a professional wrench my whole life until 2 years ago, specializing in Chrysler vehicles. Needed to get ready for retirement so I took a job that pays much better. :)

I have a 2000 outback, 177,000 mostly trouble free miles, 2.5, automatic with an aftermarket remote start that has been on the car since I owned it, approx. 4 years now. Wife and I decided to sell this Outback and upgrade to a newer model. A buddy of mine found out I was thinking about selling it, we worked out a deal, he test drove the car. On his test drive, the ABS light came on, and he mentioned the cruise did not work for him. I also found that the remote start was acting wonky. It would start the car, then shut down immediately as though the brake was applied without the ignition being on.
I have a Snap On Solus, so I plugged in and found 3 codes in the ABS system. In order they are:
54, a stop light signal circuit code,
56 a "G" sensor open or ground to short code and
23, left front wheel speed sensor,.
Cleared the codes went for a drive and all 3 codes came back. Test drove again and all 4 wheel speed sensors are reading exactly the same RPM with only 1 RPM difference from time to time. Normal.
About this time I discovered one other little problem. The CHMSL lights up with the tail lights, and then goes brighter when the brake switch is activated!! Weird. So I grabbed a new brake switch and installed it. Same issues.
Checked ALL the fuses and as many grounds as I could locate, same issues. Pulled the rear hatch cover and checked all the wiring to all the rear lights. All good with no issues found.
On the off chance that the remote start was the issue, I completely disconnected it from all the other systems. Same issues. ABS light on, no cruise, no remote start and the CHMSL lighting up with the tail lights.
My questions are these:
What in the world is a G sensor and what does it do?? I can find NOTHING about it in my Solus or anywhere online.
Why a wheels speed sensor code when it is functioning perfectly?
Lastly, what or where should I be looking at in the brake circuit for a problem? I can not help but think there is an issue there someplace....
Thoughts? Ideas??
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That generation has a common issue with the tail/stop lights. They use the 1157, which has two filaments in one bulb, with two contacts on the base. The contacts tend to flatten and can short to each other. In other cases, one of the filaments breaks, and the end contacts the other filament. If this is the situation in your case, when power is applied to the tail light circuit, the brake lights get some power as well and this is showing by the dim lighting of the high mount stop light. Also, because there's voltage on the brake light circuit even though the brake pedal is not pressed, the ABS on-board diagnostics (which monitors the brake light circuit voltage) sees an inconsistency and it turns on the ABS warning light.

There's four of these bulbs across the back, two in the fenders, and two in the hatch. Pull all four and closely inspect each, better still, replace them with new. At the same time, check inside each socket. Water does tend to get inside that area of hatch and there have been cases of conductive paths and corrosion in the sockets that cause the same rogue connection between the two circuits.

Here's a couple of similar threads:

http://www.subaruoutback.org/forums...nce/301898-light-issues-unsure-diagnosis.html

http://www.subaruoutback.org/forums...cs/249577-2002-wagon-brake-light-problem.html
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I was going to mention the light bulbs could be shorting, but someone got to it first... ^^^
That's the only thing I can think that would throw codes like that, as well as cause the remote start to intermittently shut the engine off.
Simple test, replace the turn signal bulbs...
Thanks guys,I had thought of that, but all the rear lights function as they should. I have seen the elements break or sockets go bad, and leak power to tail light side, making a bright tail light. Never thought of it going the other way, specially since they all work as they should! I did find a license plate bulb out, so all time was not wasted.

I will pull the hatch cover and check that after work tonight and let you know.
. . .
Simple test, replace the turn signal bulbs...
Just so as to not confuse, the problem arises from the dual filament 1157 brake/tail light bulb at the rear. The turn signal bulb at the rear is a single filament (7440) and would not cause this odd inter-connection between the brake and tail light circuits.

There's a different possibility at the front. The front clearance (parking) light and the "side marker' (turn signal) also share a single dual-filament 1157 bulb. In that case, if the bulb contacts short, or the filaments cross, or there's a conductive path at the socket, there could be an interconnection between the parking light circuit and the turn signal circuit. But that shouldn't involve the brake light circuit and through it, the ABS.
Also, remove the sub harness on the turn signal socket and inspect the plug contacts. I had one go bad
2
Well guys, here is the proof that a bad bulb can do some cRaZy stuff!!





THANK YOU, THANK YOU, AND THANK YOU AGAIN!!

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Dang! Those have to be the worst I've ever seen!!! What shape are the sockets in?
Dang! Those have to be the worst I've ever seen!!! What shape are the sockets in?
Sockets are in great shape!!
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Bookmarked as another good example of the bulb contact issue (with pics!).
That is caused by high resistance (causing heat at the contact point). Those sockets may look god but the connection they are making to the bulbs are not good.
Go ahead and right click-save as to your computer. I don't know how long I will keep it up on Picturetrail since we have a new puppy/pictures taking up server space. :)
Go ahead and right click-save as to your computer. I don't know how long I will keep it up on Picturetrail since we have a new puppy/pictures taking up server space. :)
Can you upload the excellent photo from your computer as an attachment to the post instead? (Go to the post, click Edit. When in edit, click Go Advanced. Scroll down to Manage Attachments. Use the tool to find the photo on your computer, select it, Upload, and that's it.) It will appear as a thumbnail at the bottom of the post. The link to the Picturetrail copy can then be deleted.
can you upload the excellent photo from your computer as an attachment to the post instead? (go to the post, click edit. When in edit, click go advanced. Scroll down to manage attachments. Use the tool to find the photo on your computer, select it, upload, and that's it.) it will appear as a thumbnail at the bottom of the post. The link to the picturetrail copy can then be deleted.

done!!
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That is caused by high resistance (causing heat at the contact point). Those sockets may look god but the connection they are making to the bulbs are not good.

Seriously, the sockets, connectors and wiring are all in GREAT shape. No corrosion and no hot spots, but they had NO dielectric grease in them at all. I think the fact that they were dry, and those bulbs are aftermarket, probably made in China, was the issue. If the lead contacts on the bulbs were of inferior material, that would be enough to cause the issue. $.02
Low quality bulbs seem to be more and more common these days.
Even many of the better known brands bulbs are very low quality.

If I remember correctly OSRAM bulbs are decent.
Those bulbs do not have a high enough wattage to melt solder! That is why I say high resistance! The heat has to come from somewhere!
Those bulbs do not have a high enough wattage to melt solder! That is why I say high resistance! The heat has to come from somewhere!
Sure, but the high resistance/heat is a byproduct of the low quality bulbs.
I'm not sure about the bulb being the problem. Could you tell me what in the bulb is causing this? If it was the solder why isn't it also showing on the ground solder spot? I only see this on the power posts, so it could be bad sockets or the crimp to the power post to the feed wires. If you look at the picture of the ones not melted as bad, you can see the indentation from the socket contacts!
The contacts are cheap and porous, perhaps the metal used has higher internal resistance or a lower melting point. I can't give you a reason based on physics analysis, I can just tell you based on experience that this wasn't much of an issue 5-10-15 years ago when bulbs mainly stopped working because they burnt out. Now it is very common to see the contacts melted across all makes and models that have aftermarket bulbs installed. And just looking at most of the bulbs sold these days you can see how cheaply made they are, especially when you have a good quality bulb to compare it to.
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