Whacko RH front turn signal

I was driving home from work - and upon using the RH turn signal, it began to flash the interior lamp in the dash rapidly. Parking lights were on - usually means the bulb's bad correct? Changed the bulb - used 4157NA. Key off and out. When the truck was started - no change. I've had three different bulbs in there, original and two new ones - same results.

LH side works fine, in every headlamp position - OFF, DRL, PARK and Headlight. The turn signal bulb works correctly and uses both elements for a bright yellow signal and DRL light.

Tried Hazard button with key off / removed. LH Lamp flashes both elements - normal blink rate. RH lamp flashes a single element - normal blink rate.

RH front lamp, light switch off single element powers up - normal flash rate but single element. Switch on DRL and normal flash continues but has no DRL second element. Switch to PARK goes to rapid dash blink - but nothing out front and same mode with the Headlights on.

This is a Limited model with the lamps in the side mirrors - they work and so do the rear turn signal lamps.

Ideas? Bulb change is usually an easy fix.........

 

Bulb finder I checked requires bulb #3157

Assuming the bulb isn't the issue I would pull the plug and checked continuity and corrosion of the socket or connectors as well as fuses.

 

U checked a lights in all functions?

 

Checked the numbers on both OEM signal bulbs (never changed before) - both were 4157NA. O- Reilly told me 3157NA and I bought a set but no difference seen. Got the 4157NA set at Autozone to get the exact match.

Checked for corrosion right away - this is an Arizona truck and seldom even wet - sockets look good - RH underhood headlamp wiring doesn't have an obvious kink or wound.

What fuse would operate only the RH turn signal? Hazard switch flashes correct rate - but not both elements in the RH bulb. Seems to indicate an individual wire or relay contact?

 

I’d wait for someone to post up some wiring diagrams so you can start tracing wires. I’ve seen bad grounds cause some whacko issues, you could look there.

I had a car that spent time in the Deep South heat. The wiring insulation had receded back exposing bare wires all over.

 

If your elements work correctly most likely you turn signal flasher module is failing.
If you were so inclined you could take it apart and look for cracked solder joints or burnt areas, the thread below shows the location of it.
https://www.tacomaworld.com/threads/12-pin-dtrl-led-flasher-modification-2012-tacoma.244028/

 

-Dm93-

Thanx MUCHO for the info - I'll go find my meter (and replace the batteries). Seems like a devious sort of operating scheme for something so simple........

 

Might be a dumb question but is that a dual filament bulb? It needs 2 filaments

Might be contacts inside the combo switch going bad. Try moving the switch very slowly through its turn signal positions and see if anything changes

 

Both the 3157NA and 4157NA bulbs are dual element amber glass.

 

The switch only tells the turn signal flasher to turn on, it shouldn't cause hyperflash.
Still a good idea to test and make sure though.

 

Might still be bad contacts in the bulb socket. Move the socket to the left side and see if the problem follows

 

No work on the Taco yesterday - morning rain and afternoon spent working on a solution for a worn crawler idler on a JD 330c lc backhoe. Maybe today........

 

To close this out - finally got a chance to get after this and get it fixed. Started with tracing the wire lead from the bulb socket - and soon found by "braille" a chewed spot in the wire loom. Directly behind the wiper fluid reservoir - out of sight - a rat chewed wound. After a few minutes struggle to get the wiper fluid wiring removed and the vessel out of the way - the white lead with a black tracer was found parted. To get this done - I used a (shudder) butt splice to reconnect. Will probably live to regret - but not in the cards to do much more today .....miserable place to work and no slack to work with. Wound it with some Scotch 33 and covered with a piece of 1/2" convoluted loom.



Thanx again for the wiring diagram - I did end up using the 4157NA bulb. Weird the way the lamp behaves with the ground lost.......

 

Nuttin wrong with a few butt connectors. At least you found it

 

For sure better than the "twist n tape" I see done all the time although I would recommend the heat seal ones to prevent future problems.