Brake-light switch is possessed

Rickl · Mar 30, 2012

Pim said:
These may help
Greetz

Pim, are those drawings for your 1997 RAV4?. The drawings I found are for a 1999 model, and there are quite a few differences. Perhaps the euro version is different than the North American version.

Pim · Mar 30, 2012

No, the wiring diagrams are actually from a 4.2 model, but i don't have anything else to go with and figured they wouldn't be that much different. If you have others, please share.
The hitch thingy is for the RAV4, without specification which year.
Greetz

Pim

T-Dogg · Mar 30, 2012

Thank you, Pim. I likely am not knowledgeable enough to make use of all of this, but the wiring map specifically for the 3-door may prove very helpful. As for the access to the trailer harness, Rick, I'm pretty sure I have to deconstruct the interior trim back there to get at it. Later generation RAVs allow access to change bulbs from inside the vehicle, but 4.1s make you unbolt the assemblies from outside. I will do what I have to, but right now I must go install a toilet here at work! The fun never stops some days.

Thank you, gentlemen.

John

Rickl · Mar 30, 2012

Pim said:
No, the wiring diagrams are actually from a 4.2 model, but i don't have anything else to go with and figured they wouldn't be that much different. If you have others, please share.

All I have is a drawing of the Exterior Lamps Circuits. I obtained this in paper form, and have scanned it into a PDF file. The quality isn't the greatest, but if you want it here it is. (not sure how long this link will be valid)

JuneBug · Mar 31, 2012

Rickl said:
All I have is a drawing of the Exterior Lamps Circuits. I obtained this in paper form, and have scanned it into a PDF file. The quality isn't the greatest, but if you want it here it is. (not sure how long this link will be valid)

That's an excellent schematic, Rick. Looking at it I can definitely support your theory of an open ground. That would cause the voltage for the brake light to backfeed through those other lamps and cause strange problems. It also shows the approximate locations of the ground point. I would start by finding that and cleaning it up.

T-Dogg · Mar 31, 2012

Gee, that schematic actually seems to have been created for us regular people...it's even in English and makes sense. I'm finally home from work but thunderstorms are rolling through Pittsburgh right now, so this will have to wait till tomorrow. I am hoping for the odd benevolent lightning bolt to slap some sense into what was a perfectly happy lighting system until a couple of weeks ago. But I thank all of you for your generous input. Once I figure this out I will post the solution in case anyone else suffers this unpleasant fate.

Grateful in Pgh,

John

T-Dogg · Mar 31, 2012

Success! Rick, James and Pim, I don't know how to say how grateful I am for your help. It was a long, gloom-filled ordeal that took most of the afternoon, but the demon has been vanquished. Feel free to ignore the blow-by-blow that follows, but I can't resist.

First I removed the right taillight assembly because I re-read all of your posts this morning and realized I hadn't tried removing all the bulbs on the right side. No good. Then the left side; nope. I then proceeded to remove the plastic trim to access the control unit Rick described for the trailer harness. No unit, just plain old splices over the left wheel well. I turned on the flashers and wiggled everything in hopes of finding the problem. No luck. I checked the ground bolts on both sides. I was getting discouraged so I started trying anything I could think of: removing the front parking light bulbs, crawling under the dash and removing the brake-light switch connector, pushing every fuse and relay I could find to make sure they were tight, and then basically doing it all again. Finally I said, "desperate people do desperate things," and grabbed my cable cutters and severed each of the trailer harness wires near the splices. I was afraid if I disassembled the connectors I'd never get it right again. That was it.

You guys are the best. Someday soon when I'm done renovating my house and have 30 seconds to spare, I will spend some relaxed time on here and maybe do someone else the favor you have done for me. For now I can tell my friends I had a car problem so tough it took experts from three countries to solve it.

Your friend in Pittsburgh,

John

Rickl · Apr 1, 2012

T-Dogg said:
Success! Rick, James and Pim, I don't know how to say how grateful I am for your help. It was a long, gloom-filled ordeal that took most of the afternoon, but the demon has been vanquished. Feel free to ignore the blow-by-blow that follows, but I can't resist.

I'm glad to hear you repaired the problem, and it's great that you got back to let us know what the final problem was. So many times we never find out how a problem was resolved. I'm surprised that you didn't find an electronic controller.

Smaller trailers often have one red light on each side. This light is a dual filament bulb with one filament acting as the taillight and the other filament serves as both a brake light and turn signal. When you have amber turn signals on the vehicle,the controller combines the separate brake and turn signals into a single lead to feed the trailer light. You can get more information about trailer wiring here.

It looks like the cable you removed must have become damaged and shorted out the individual conductors. As I said it may have become pinched in the door opening or other area. Did you remove that entire cable and examined it from end to end to see where the damage may have been, or perhaps find a controller hidden along it's length?

T-Dogg · Apr 1, 2012

Rick, I don't know what such a controller should look like, but I thought of something after reading your post that could explain it. The connector at the trailer end of the harness has five wires going into it but only four terminals on the other end (three female and one male). Since this hitch came on the car (though likely dealer-installed), I'm thinking that connector is actually the controller your referring to. It seems to be larger than it needs to be if it's just a connector. One of the female terminals has a large amount of blue-grey corrosion in it, which may mean something or other in this episode. The hitch went unused until I bought the RAV a year and a half ago, but I have hooked up a small utility trailer a few times, and if there was a cap on this connector I've lost it, allowing exposure to weather and salt. Whadyathink?

Rickl · Apr 1, 2012

T-Dogg said:
Rick, I don't know what such a controller should look like, but I thought of something after reading your post that could explain it. The connector at the trailer end of the harness has five wires going into it but only four terminals on the other end (three female and one male).

It sounds like you are descibing this connector

According to the charts here, The 4 wires attach like this White=ground (unprotected contact), Tail=Brown, Yellow=Left Turn, Green=Right Turn. So you can see that there is no conductor for the brake lights. That would be the signal on the 5th wire.

The controller would send the brake signal to both trailer lights when required, but then flash one of the lights when the RAV's amber turn signal was on. I have never seen a controller built into the exterior connector before. They are normally kept out of the weather to prevent problems like you experienced. However if you have 5 wires going in to a thicker device than the image above, then that must be it.

Just as an FYI here is a link to many different types of adapters.

Thanks again for letting us know what you found, as I'm sure it will help others in the future.

T-Dogg · Apr 1, 2012

Rick, I'm attaching a thumbnail you can blow up to see what I have. I also found the installation instructions in my glove compartment with both the Toyota and Reese trademarks, so apparently that's who supplied the dealer-installed hitches on the early RAVs. Those instructions refer to a "converter connector," which I think is what you're calling a controller. I'm not sure how long ago they started using separate amber turn signals, but I guess they needed some time to realize that hanging this unit out in the weather wasn't such a good idea. Anyway, many thanks again. I feel like I'm back from the Twilight Zone.

All the best,

John

Rickl · Apr 2, 2012

T-Dogg said:
Rick, I'm attaching a thumbnail you can blow up to see what I have........... Those instructions refer to a "converter connector," which I think is what you're calling a controller.

Yes that connector is a converter, and converter is the correct term. I don't know why I started using the term controller, because a trailer controller usually refers to a brake controller, an entirely different thing.

T-Dogg said:
Anyway, many thanks again. I feel like I'm back from the Twilight Zone.All the best,John

Your welcome, I'm glad you were able to resolve the problem.

Pim · Apr 2, 2012

*imagines seeing this thread blown up like T-Dogg suggested by 'blow up the thumbnail'*

*runs off scared* AAAAAAGH AL QUAIDA!

T-Dogg · Apr 2, 2012

Ha ha, reminds me of my conversation with the secretary where I'm doing physical therapy for my back. After we'd scheduled a few appointments, she said, "Don't worry, if you can't make it we can just take you out." Being the smart-ass that I am, I said, "So, you kill people who don't show up?" On that note I'll take my exploding thumb and leave quietly.

John

Dr. Dyno · Apr 2, 2012

I recall seeing one of those converter/connector modules, but it was many years ago. From the looks of the picture the corrosion on the terminals has probably also crept up them and into the electronics too. Sounds like an autopsy is called for.

T-Dogg, you'll need to replace it with the separate converter and connector that's common these days. That'll keep the converter safely inside even if the connector is allowed to hang out.

On all my occasional use tow vehicles I also install the cable & connector so I can leave them inside out of the weather when not in use. To use it I pull out as much cable as I need, lay it on the trunk (boot?) gasket and close the trunk lid or door. There's allways enough gap so the flat cable isn't damaged. Just be sure you don't sever it in any latches! :wall

T-Dogg · Apr 2, 2012

Thanks, Fred. I had just begun to shift from the "ah!" of a successful repair to the "duh" of how to keep it from happening again. I use the hitch maybe three times a year, so your post is just what I need as I put things back together. Thanks.

John

Brake-light switch is possessed

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