Left side hyperblink is driving me nuts

I have a 2012 DCLB TRD Sport and randomly last week I started to get a fast blink on the left side. I changed the bulbs, I changed the sockets side to side. I swapped taillamp socket harnesses side to side, still staying on the driver side hyperflashing. I tried plug and play resistor harnesses, didn’t change anything. But when I put 2 sets of harnesses on the driver front or driver rear, it flashes normally but the dash odometer dims. Anyone else have this happen. I would really hate to get into a wiring harness replacement. I posted up some videos. I can’t find any LED Relays, and my blinkers arent LEDs... I just figure that would be the easiest fix. The Diode Dynamics one doesn’t work on trucks with DTRL. Any ideas?

 

Have you checked your ground at your left side bulbs, sounds like you may have a bad ground or a faulty flasher relay.

 

if the relay itself was bad wouldn’t it happen whether it was right or left turn? First thing I thought was relay. Swapped all conceivable harnesses and bulb connectors as well as brand new bulbs. And I haven’t changed any mods in a while. Just happened last week.

 

Try replacing with regular halogen bulbs

 

Does the front and rear blinkers actually blink when it is hyperflashing?

Sounds like a high resistance circuit to me. Check wiring and sockets. Also make sure you are getting the bulbs seated correctly in the socket.

 

The relay has separate relays and timer circuits inside for left and right so theoretically you could have a problem with it but as @Jimmyh said you need to rule out voltage drop/high resistance in the wiring first.

 

If you have the tow package be sure to check the wiring there too. Check inside the plug for corrosion, the wiring coming into it for cuts or damage

 

Change your flasher

 

my truck came with LED tails and had the original blinker bulbs in DRLs. I replaced the bulbs with standard sylvania long life halogens. I don’t have LED blinkers, and all lights function. There are zero lights actually out. I replaced all halogen bulbs with halogen bulbs. I posted videos on the FB Tacomaworld but won’t let me link them.

 

So it does have left and right separate relays in the single flasher unit? It starts flashing normal land then speeds up only on the left side.

 

It's quite a complex little unit for a flasher, here's a thread with pictures of it.
If your inclined you could take it apart and look for any burnt components or cracked solder joints.

https://www.tacomaworld.com/threads/12-pin-dtrl-led-flasher-modification-2012-tacoma.244028/

 

This might be a dumb question but...

You mentioned tails..but did you check the front blinkers too? Guessing yes but just trying to rule out the obvious.

I'd second what @Geeves77 said re the flasher as well if you didn't check that.

 

So all the exterior lighting is stock/oem?

Are you sure you have the correct amber bulbs in the front? They should be dual filament. Did a single filament accidentally get installed?

 

The bulbs in the front are factory 4157. I also swapped the bulb sockets from side to side to see if it followed left to right. I also replaced both front bulbs with new Sylvania Long Life Dual Filament. I tested the trailer harness even and each of the signals is powering up properly. I’m thinking it has to be the flasher unit itself.