Another Fast Turn Signal Thread (1 Viewer)

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I know there are several threads on this issue, and I have read every single one that I can find. But, haven't been able to fix the issue yet. 1997 LC. Left blinker blinks twice as fast. The left rear bulb does not flash. No LED bulbs anywhere. The problem started about 3 months ago, but was intermittent. It's been consistent for the past ~5 weeks now.

Here is what I've done.

0. (In all the steps below I've applied permatex dielectric to each connection/socket along the way)

1. Replaced both front and back bulbs (non-led) bulbs on the left side. Same issue.

2. Verified both of the new bulbs worked, by putting them into the right blinkers.

2. Swapped the bulbs from the right blinkers (which work fine) into the left blinkers. Same issue.

3. Replaced the blinker relay behind the dead pedal (not fun) with a new OEM one from the dealer. Same issue.

4. Disconnected, cleaned (wire brush) and applied dielectric grease to all 3 of the ground connections. (EA, EB and BG in the EWD manual. Pages 30 and 36).

5. Checked the connections in the left rear panel (where the jack and tools are stored). When I say "checked" I mean I disconnected each of the connectors, looked for corrosion, applied some dielectric, and reconnected.

6. Disconnected the trailer hitch wiring harness behind the spare tire. Had trouble finding specific documentation for this, but the connector I disconnected is linked below. This connector was super corroded inside, and when I disconnected it, neither the left or right rear blinkers worked. I cleaned out the connector as best as possible, applied dielectric, and reconnected. Nothing changed. Is there a way to fully disconnect the trailer wiring upstream in the left rear panel where the tools/jack are stored? Here is an image of what I disconnected: Trailer Hitch Wiring 1991-1997 FJ80 FZJ80 : CruiserParts, The best place for Land Cruiser Parts! - https://shop.cruiserparts.net/index.php?main_page=popup_image_additional&pID=827&pic=0&products_image_large_additional=images/trailerhitch_01.JPG

7. I have ordered the tiny blinker lights for the rear-side blinkers, but I don't think these are the cause. I wasn't even aware there were bulbs in there, and neither side has worked since purchasing this vehicle. Plus the right side is also burnt out, and isn't causing the right blinkers to fail.

8. Took out the multimeter (not my forte), and tested the right side (which works) and was getting 0/12/0/12/0 volts when blinking. The left side (not working) was getting 0/1.6/0/1.6 volts, which I'm assuming means I have a bad ground somewhere.

I've also been looking for worn wires along the way, but haven't seen any. My guess is this is related to trailer wiring, but not sure what to do next. I need to pass a state safety inspection in about a month, so I obviously need to figure this out asap.

Thanks for any help you can provide.
 
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have you thoroughly cleaned out the bulb socket?
 
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It's a lightbulb. Either you're not getting +12 or there's a bad ground. What were you using for ground when checking the bulb socket? Have you tried a body ground? That would help you determine what you're missing.
The rear side marker lamps are running lights, not turn signals. They come on with the parking lights.
The blinker relay is 1 device that feeds all lamps. Have a look at the EWD.
 
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It's a lightbulb.
Wouldn't swapping right/left in step 2 have eliminated this?

Either you're not getting +12 or there's a bad ground. What were you using for ground when checking the bulb socket? Have you tried a body ground? That would help you determine what you're missing.
I'll check it against the body whenever it stop pouring outside. Wasn't doing that.

The rear side marker lamps are running lights, not turn signals. They come on with the parking lights.
10-4, I saw someone in another thread say they were turn signals. Good to know. Never even knew there were bulbs in there. Thought they were just reflectors.

The blinker relay is 1 device that feeds all lamps. Have a look at the EWD.
Yep, I've been looking at it. Looking at the diagram below, coupled with the bad corrosion in the trailer wiring socket below the vehicle makes me think there is some kind of ground issue with the trailer socket upstream of the bulb that won't blink.

Thanks for all the help!


1660071106568.png
 
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Looking at the diagram below, coupled with the bad corrosion in the trailer wiring socket below the vehicle makes me think there is some kind of ground issue with the trailer socket upstream of the bulb that won't blink.
Look closer at the schematic. The bulbs have a hard ground to the body. The trailer harness connectors feed +12 to the bulb sockets. So if the trailer harness was the issue, you wouldn't be getting +12 to the bulb socket. I'd be checking for +12 at the trailer harness.
Pin 1 of T5/T6 is the right rear (green/yellow stripe) and pin 2 is the left rear green/black stripe).
If the connectors are corroded, then cut them out and splice them back together.

Or, cut out the old connectors and splice in new ones to keep it OEM.
90980−10214 female connector housing
90980−10213 male connector housing
82998-12050 male pins w/pigtail
82998-12580 female pins w/pigtail
 
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Joined
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Look closer at the schematic. The bulbs have a hard ground to the body. The trailer harness connectors feed +12 to the bulb sockets. So if the trailer harness was the issue, you wouldn't be getting +12 to the bulb socket. I'd be checking for +12 at the trailer harness.
Pin 1 of T5/T6 is the right rear (green/yellow stripe) and pin 2 is the left rear green/black stripe).
If the connectors are corroded, then cut them out and splice them back together.

Or, cut out the old connectors and splice in new ones to keep it OEM.
90980−10214 female connector housing
90980−10213 male connector housing
82998-12050 male pins w/pigtail
82998-12580 female pins w/pigtail

Ok, this was a lot of help. Thank you. I'm back up and blinking with a (hopefully) temporary fix. I tested the voltage on the 9pin (left-side) and 10pin (right-side) of BU1, and both tested at full +12v, as I hoped. I then checked the voltage entering the trailer socket. The left side was only +1 to +3 volts. The right side was a full +12v. So, something downstream of BU1 before the trailer socket is causing the voltage drop for the left side. As a temporary fix to pass inspection, I've tapped into the G-B wire upstream of BU1, and wired it directly to the bulb socket of the left-rear turn signal. I've also gone ahead and disconnected the trailer socket entirely as I only ever tow with my Tundra. This has resolved the issue enough for me to hopefully pass inspection. I've tested left-turn, right-turn, brake, reverse, and hazard lights and all are working as expected

I'm telling myself I'll come back and fix this correctly after passing inspection. Hopefully, I'll find the time to follow through with that and post here once more. Thanks again.

For future reference in case you don't have the EWD, here is my hack fix. Ok, now everyone roast me... 🔥

1660150101644.png
 
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My rig recently developed the same problem. It’s on my “to do” list.
 

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