Left turn signal goes on with brake application??

[aim]

Conductive salty crap in one of the connectors? I have rust in the 80's quarter panels and salt spray from the right rear wheel gets into all the connectors. When it rains, my rear wiper turns on by itself, the truck continues running with the igntion if the rear defroster is on, etc. I'll fix the rust eventually, but in the meantime I cleaned the connectors and alleviated the symptoms...

 

[gray]

My rig has almost zero rust; none on/in the panels. The frame looks better than a northern rig after a couple of seasons. The trailer connector dangling in the wind just turned green from road salt in the last few weeks while traveling up north. Of course, the road salt could have gotten into a harness somewhere; they should ban that stuff as harmful to the health and safety of our rigs. I pulled the trailer connector from the box in the cargo panel which didn't change anything however. I will look closer when I get a sunny day. I still would like to find the problem area.

The torrential rain storm I drove through for 6 hours straight on the interstate yesterday completely cleaned the undercarriage and even the front of the engine where I had oil stains and some build-up from seeps, amazing. Maybe it cleaned the area involved and it took a day to dry out??

I had never before driven in rain and winds that intense for so many hours, ever. At a few points the vehicle suddenly slowed down as if a giant hand was holding it back. These were not due to water on the road (had that too, in buckets) but intense gusts of wind. My arms still ache due to using both arms on the wheel for so long; usually it is hands in the lap steering.

 

[gray]

Symptoms came back today, then after driving a few minutes, they went away; any more suggestions.
I have disconnected the trailer module and cleaned the negative battery post and neg battery wire connection.

 

[landtank]

First thing this morning before heading out I opened the PS cargo panel, reached in and pulled the connector out that goes to the trailer wiring; but no change in symptoms. (did not check for the green wire at that time)

Did you unplug the harness that goes out to the 4 pin connector or actually remove the module? have you removed that green wire that is plugged into the DS tail light?

 

[Beowulf]

Did you unplug the harness that goes out to the 4 pin connector or actually remove the module? have you removed that green wire that is plugged into the DS tail light?

Rick ===>



-B-

 

[gray]

Landtank; I unplugged the harness connector that was on the rear side of the module. I looked at the rear of the panel and saw no solo green/bare wire. There was a small wire bundle attached to the body in the location of the bottom rear of the panel; it was inside a black plastic corrugated split cover. This bundle then splits; one group of wires from that goes up toward the PS rear lights and the other goes toward the DS; I'm guessing that is where the green wire is? There were also many other unbundled wires; a few that were apparently green. Once I get my cargo area a bit more empty and the sun comes up tomorrow (too busy during daylight) I'll dig deeper. I did look at my DS light assembly;did not see anything that looks non-factory; not sure about the wire colors (it is dark); just one green wire I think. Hard to tell which is the port installed wire; they all look factory.

 

[gray]

Well, leave something alone and it will get better on it's own, right? Was afraid I might cut the wrong wire (before) and the problem went away (or so I thought) and the weather has been bad, yadda yadda yadda.

Today,as suddenly as it started (and stopped) before, it started up again.
But instead of the left turn signal coming on when I pressed the brake pedal as before, today it was the right. Then instead of the cruise control shutting off completely when I flipped the turn signals, today when I hit the brakes the cruise did shut-off, but as soon as I took my foot off the pedal, it not only came back on, it started to accelerate. Then after stopping to get something to eat, I come back to the rig and the brake interlock is apparently not working and could not pull the shifter into gear; so had to push a pen down into the convenient slot Mr T put there for us. Whew. Hoping it didn't fry something, but probably did.

Bad weather again and dark, but did look behind the DS rear cargo panel and could see that the rubber grommet around the wiring harness (that goes out the lower panel to the trailer connector) had been pulled out?? Noticed same for the wiring that comes out from under the rear sill plate to the plate lights. It actually looks like someone or something pulled on it?? Someone playing around yanking on the trailer harness for giggles?? A 10 pound build-up of ice dragging it out? Or, just from old age and it rotted out, who knows. Could not get to the all the wires, I will have to remove the bracket that holds the hydraulic jack to get a good look; one or more wires felt rough but could not visualize them directly. Will attempt to identify the correct (solid) green wire and look at the other wires and fuses etc when there is some daylight. I did see an small unused blue connector on the DS taped to the bundle, wonder what that is for?

OK, hit me.

 

[gray]

Haven't found the main culprit yet, but did discover, as others have, that I blew the 10A brake (stop) light fuse, which would explain the brake-shift interlock not clicking/operating. Assume that also confirms that I have a short somewhere in the brake light/trailer harnesses. Looked as best as I could at the trailer harness, but could not find a bare wire or wire that had lost it's insulation, however both of the rubber grommets that wrap around the trailer harness had pulled free of the panels where they are supposed to seal/protect the harness. Will have to get a stronger flashlight and maybe get it on a lift to look closer. Wondering, if I replace the 10A fuse so that I have brake lights, other than it popping again, is there any risk to doing other damage??

Also, cleaned a couple of grounds today (front fenders) and the battery neg terminal; too dark to do the rest. The grounds appeared to have never been messed with since the factory, no gross corrosion, just a tad of darkening of the bolts and loops, a tad of light rust on the threads that went into the fenders. Used fine grit sandpaper to clean everything, cleaned them up with electrical connector cleaner, put them back in.

 

[Beowulf]

You said you removed the module that controls the trailer wiring and now you are saying that you are still "looking" at it.

Post pics. Nothing you are saying makes any sense. We need pics of the wiring behind the panel on the right side of the cargo area. That is where the trailer module is. We need to see what you said you removed and what you are now telling us you are looking at as the problem. We need to see the sill area and the far right side of the cargo area floor as it crosses the sill and goes into the wheel well (with cargo panel removed.) We need to see the taillight area in the driver side cargo area; whatever wiring and connectors that you are talking about. Same with the right side taillight.

These threads that go on for months are tiresome gray.

-B-

 

[gray]

Haven't been driving it much since the problem first started about three weeks ago. The farthest was yesterday, when things popped back up.

I previously pulled out the connector that goes into the trailer module: no change. I did identify the small bundle of wires going to the PS (right side) brake lights. The module itself is still stuck to the inner quarter panel, but is not connected to anything.

I did not see any wires crossing over the floor of the cargo bay or near the sill with the sill plate removed, but will look more tomorrow.

I did locate what appears to be the main wire bundle for the trailer harness; it is located behind the DS cargo panel and below the hydraulic jack plastic mounting bracket (I removed the jack and bracket for better access)

This harness (left side, DS) sends wires to the DS lights, it also sends a smaller bundle of wires underneath the vehicle out to the bumper/tow hook. Haven't yet found how the wires cross over to the PS (right side). I may have time tomorrow to look harder for that bundle.

Sorry, don't have a digital camera. Maybe it is time.

 

[reffug]

You said you removed the module that controls the trailer wiring and now you are saying that you are still "looking" at it.

Post pics. Nothing you are saying makes any sense.
These threads that go on for months are tiresome gray.

-B-

uhm yep.

 

[gray]

(9 jan to 30 jan= 21 days with a break mostly due to the problem disappearing during that time)

From previous posts;

"---I unplugged the harness connector that was on the rear side of the module"

"I have disconnected the trailer module--"

To recap:

The harness that I was still trying to get a good look at is on the DS, the module is on the PS. Up to this point, I have not been able to identify any obvious damage or bare wires touching metal, however, that is what I suspect also.

The dangling black rubber trailer connector (outside near the bumper) that is meant to actually plug into a trailer is corroded to some extent

Never found a single green wire under or near the sill. My guess is that my rig was wired differently than some others? Maybe each port (or each installer) did it slightly differently, or, there was a change in the process as mentioned previously.

I did find a solid lime green wire on the DS, behind the cargo panel. It is a larger gauge than the other OEM appearing wires.

My best bet at this point from what everyone has mentioned, and as we know the 10A brake lights fuse blew, is that there is an intermittant short in the small harness that runs from the DS cargo area to to outside black rubber trailer connector.

That short section appeared as though it was laying down on the sheet metal where the rubber grommet had failed, as it exits the bottom of the cargo panel (ie: below the stored jack) going out to the bumper. The short could also be in that outside trailer connector itself, also mentioned by someone previously.

I hope this is clear for anyone reading.

I've talked to a Toyota service manager with 27 years experience; he said he knows of the problems with these trailer harnesses, said he just worked on one last week. I will let everyone know what they find

Appreciate all the helpful comments.

 

[lathamb]

I hit a rock and pinched off the trailer wires that were hanging below my trailer hitch. The next time it rained, all sorts of wierd stuff started happening. Wipers stopped working (not good), fuzes blowing right and left, wouldn't shift out of park. I snipped off the rest of the wire from the trailer wiring harness and taped it up and all was solved. I still need to remove the harness all together. I found out that night that most gas stations around me didn't sell fuses (anger management).

 

[gray]

Here is the feedback from the dealer that looked at it today:

The problem was in the black rubber 4 pole connector/plug, period. I had looked at it and saw some corrosion on the contact surfaces. What I had not noticed previously, and did not know to look for, was that the connector itself was bulging slightly. This meant the corrosion was not just on the contact, but was deep inside the connector. This was the answer. Problem solved. Hope this helps someone else; if the 4 pole trailer harness connector/plug that dangles off your tow bar is swollen and you see any corrosion by looking into the contacts, it probably needs replacing. Not sure if CDan can get replacements, I was told by the local dealer parts guy that the complete harness is no longer available, but I would assume that the trailer connector/plug is a generic part. I do know that auto parts stores usually carry a selection of them.

If anyone wants to read the rant about the rest of the story, I put it in chat.

 

[Beowulf]

Something does not make sense gray. You said you completely removed the trailer light module from the system as several requested you to do. If you had done that, the 4-pole plug would be completely disconnected at the same time. Did you remove the module then plug it back in? That would be the only explanation for the 4-pole plug to have any effect on the system.

FYI, those 4-pole trail light plugs are available everywhere. I have seen them in convenience stores, Walgreens, Target, and everywhere else. No need to bother Dan for that.

-B-

 

[gray]

1) The port installed module was disconnected from the system about two weeks ago. It has remained disconnected for two weeks. The symptoms got worse a few days ago, hence the trip to the dealer. The module is still stuck on the inside wall of the quarter panel, but not connected to anything.

2) No idea what is the correct answer; that is what I was told today by a Toyota Master Mechanic. They apparently did nothing to try to diagnose the problem and just pulled the harness apart as it was an easy fix (for the brake lights, etc). The wires they pulled (?4) are all solid colored, larger diameter than OEM wires in that area, and are located behind the DS cargo panel; they were all connected to the OEM harness, but are not anymore.

 

[Beowulf]

Your truck is a mess. Someone has installed a second trailer wiring module or something because if you unplugged the "normal" module then the 4-connector plug would not be connected to anything and would not cause your wiring problems.
-B-

 

[lagwagon]

As harper68 said check the bulbs. I know they pulled the harness but every time I have seen this, someone has installed 1157 US style bulbs instead of the proper bulbs. The contacts can touch the turn signals to the brake lights and cause all these systems. They could have changed your bulbs.

 

[gray]

lagwagon, which bulb type are you saying is the correct type for the brake lights?

 

[lagwagon]

Strike that, reverse it. The 1157 is the correct bulb. The 1156 has the single element.