I turn on the left signal, dash lamp blinks, and front and rear lamps blink. I turn on the right, and the right dash lamp blinks. So does the front and rear tail lights. All perfectly normal. I step on the brake, and the left dash lamp is on solid. So are the front and rear left turn lamps. What do you think? I replaced the trailer module with an aftermarket many moons ago, and it's been working. Could it have finally failed? Or is it something else? Thanks.
Turn signal weirdness
- Thread starter 4SKIN
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RodrickHeffley
Member
Sounds like a bad wire in the taillight or its harness, it could be connecting to the brake light when you hit the brake which is turning everything on
ArthurKotb
Member
Have you modified the bulbs to be LEDs?
Have you replaced any incandescent bulbs recently?
Have you replaced the flasher? (I've never replaced a Toyota flasher; never had one go bad, but it's a possibility.)
Have you made any changes, electrical or mechanical, recently?
Have you replaced any incandescent bulbs recently?
Have you replaced the flasher? (I've never replaced a Toyota flasher; never had one go bad, but it's a possibility.)
Have you made any changes, electrical or mechanical, recently?
phattyduck
Elite Member
Step 1: temporarily remove trailer harness
If that doesn't fix it, you may have a bad flex circuit board on the back of the cluster. I had to replace mine a few years back for similar weirdness.
-Charlie
If that doesn't fix it, you may have a bad flex circuit board on the back of the cluster. I had to replace mine a few years back for similar weirdness.
-Charlie
What I have done was replace my trailer lamps with LED's. Checked all the bulbs on the vehicle, first thing I did, and they are good. I know the trailer is wired correctly, but I'll check that also. I have a suspicion that the 4way to 3way converter is fried. Could be something I did while messing with the tailer wiring. I put a new one in years ago because the original failed. It's been so long ago that I don't remember why I had to change it. I'll do more diagnosing this week end. Thanks.
ArthurKotb
Member
Like Phattyduck says, disconnect that harness to isolate vehicle from trailer so you can determine which one has the problem.
You said you checked all the incandescent bulbs on the 4Runner. Do those have the brass base with the 2 nibs, one on each side? My other car is a 99 Sienna and it uses those. It's possible to install those backwards. One nib is higher than the other, matching the indents in the base. They can be forced to have brake and running light backwards. I'm sure you're aware of that, or they had changed the bulb type for your MY T4R.
Just spitballing here. Can you try removing some of the bulbs to see if you can isolate the problem? Say, take out the L/R turn signal bulb and see what the rest do?
You said you checked all the incandescent bulbs on the 4Runner. Do those have the brass base with the 2 nibs, one on each side? My other car is a 99 Sienna and it uses those. It's possible to install those backwards. One nib is higher than the other, matching the indents in the base. They can be forced to have brake and running light backwards. I'm sure you're aware of that, or they had changed the bulb type for your MY T4R.
Just spitballing here. Can you try removing some of the bulbs to see if you can isolate the problem? Say, take out the L/R turn signal bulb and see what the rest do?
Devbot
New member
+1 for removing it and seeing what happens, it's not like the trucks gonna brick itself or anything. It's possible that, say, wires were rubbing against metal and eventually wore through the jacketing, causing a short eventually. The way I see it is that's where your common denominators all hang out together; trailer harness, brake wiring, turn signal wiring. Seems more likely than the other end of the vehicle
Personally I would also take a quick peek behind the dash just to rule out any rodents too... doesn't take more than 30 minutes all said and done. Just last year I found a dead mouse smushed between my brake caliper and rotors that definitely wasn't there a few days prior - and I don't live in a wooded area or park near fields or anything. Those buggers just move in quickly if they feel like it
Personally I would also take a quick peek behind the dash just to rule out any rodents too... doesn't take more than 30 minutes all said and done. Just last year I found a dead mouse smushed between my brake caliper and rotors that definitely wasn't there a few days prior - and I don't live in a wooded area or park near fields or anything. Those buggers just move in quickly if they feel like it
It was the converter. It lasted for many years ( good quality Reese) until I replaced my utility trailer lights with new LED'S. I could not find one like it locally so I go to AtoZ. I was about to order it until I saw in the description, NOT COMPATIBLE WITH LED LAMPS. I bought a Hopkins at Autozone that is compatible. Don't know exactly why it failed, but I believe there is some kind of diode that prevents back feed and it doesn't like LED'S. They fry it. So this is something people should be aware of. Thanks for all your input on this problem.
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