HELP! Gen 3 Tail lights won’t work at night!

There are two sets of red lights on the rear of the car, the brake lights and the tail lights. They’re both in the same housing, but the lamps, fuses, circuits and wiring are different.

If tail lights aren’t working on either side, and the license plate light also isn’t working, then the most likely cause is a blown 10 ampere TAIL fuse in the instrument panel. See the section “Checking and replacing fuses” in the Owner’s Manual (PDF), starting on page 462. The TAIL fuse is item 30 in the diagram on page 468.

 

Or, your switch is in the DRL position?

Posted via the PriusChat mobile app.

 

Gen 3 (or 2010 and 2011 anyway, I'm not sure about the refresh) use the same array of LEDs for brake and tail; they are just dimmer for tail.

I agree that, as the license lights aren't on either, there's probably just something up with the tail circuit.

-Chap

 

Was it fuse 30?

Posted via the PriusChat mobile app.

 

...and why did it blow?..

 

I have the same problem! I just got back from the dealership who wanted to charge me $1100 to replace both taillights! So fuse #30 in the front left panel appeared to have blown (from my limited knowledge of nothing about what a blown fuse looks like except for the diagram in the manual) to me so I replaced it with a new fuse but the tail lights still won't light up! Should I take it in at this point? Any help would be appreciated.

 

It would be surprising, but not impossible, for the rear combination light assemblies on both the left and right sides to fail simultaneously.

Here are some questions that might help find the trouble:

Does the instrument panel illumination (the lights that help you see the switches at night) work? You might need to turn up the brightness to be sure; see page 184 of the Owner’s Manual. The illumination is controlled by the same switch and TAIL relay as the tail lights, but it uses a separate fuse, so if it works, then the trouble isn’t in the switch or relay.

Does the problem affect both the left and right tail lights? If so, it’s probably not just a loose connector or broken wire, since there are no connectors or wires that serve both the left and the right.

If you turn on the tail lights, are the license plate lights and front parking and marker lights also dark? These lights are also part of the tail light circuit and share the same fuse, so if the fuse is blown, they should also be affected.

If you turn on the hazard warning lights (four-way flasher), do both of the rear turn signal lights work? These have a separate power circuit, but they share the same connections from the rear combination light assemblies to ground, so if the turn signals work, then we know the trouble isn’t an open ground connection.

Do both of the rear brake lights work? As @ChapmanF kindly corrected me above, the brake and tail lights use the same LED modules, so if the brake lights come on, then the LED modules are unlikely to be faulty, though there could be a problem with a resistor or diode, also part of the rear combination light assemblies.

Did the replacement fuse also blow? Now that you’ve seen new and blown fuses, you might be able to tell by looking at it, but the best way is to measure its resistance with a multimeter. A digital multimeter is, by the way, essential for automotive electrical troubleshooting. If you’re not working on the hybrid system, with its higher voltages, an inexpensive meter ($10–$15) is fine.

If the answer to each question is yes, then there is probably a short in the tail light circuit wiring (wires, connectors, or junction connectors) or in one of the six light assemblies connected to it: the left headlight assembly, right headlight assembly, left rear combination light assembly, right rear combination light assembly, left license plate light assembly, or right license plate light assembly. There could also be an internal short in the instrument panel junction block assembly.

While troubleshooting, I highly recommend referring to the Electrical Wiring Diagram and Repair Manual, both available by subscription to techinfo.toyota.com or through the ChiltonLibrary service from one of your local public libraries (SPL, KCLS).

 

I'm having this same problem with the tail lights and license plate light. This forum helped me find the blown fuse, but the replacement fuse blew immediately upon installation and turning on the lights. Any suggestions for troubleshooting?

 

Found mine fuse box underneath the dash board left hand bottom corner replace the 10A blown fuse. Now the taillight worked again! Much much appreciated for this forum topic help.

 

You might be lucky, but often stories that end with "so I replaced the fuse that had blown for some reason" haven't really ended yet.

 

a fuse doesn't blow 'just because' /
next thing might be a melted wiring harness.....

 

If you replace the fuse with an oversize one ....

My dad bought a used Ford LTD once where the previous owner had done that.

The car had a sheet-metal edge between the roof and the C pillar, hidden behind the headlining. The power to the dome light ran from the dash back along the floor on the driver's side in that big wire bundle under the carpet, then up the C pillar and across the headlining to the dome light.

When the wire insulation finally wore through on that sheet-metal edge and blew the dome fuse, the previous owner put in a 30 amp fuse instead.

Shortly thereafter, the car was sold to my dad.

When I took out the seats and the carpet and pulled out that whole wire bundle, it was like a stick. Then I bent it a little, and all the insulation fell off as powder and flakes.

 

Hello guys , 2013 Prius Three here (180k miles if it matters)with issues, can’t really afford hundreds of dollars on Dealership diagnosis (especially since my mother is fighting breast cancer), and tried to fix my tag lights & my tail lights by myself, unsuccessfully until now.
Stop lights work(braking),so I tried replacing the tag lights bulbs (with leds) , still did not work.
Then I bought and replaced the blown 39 cabin fuse ( TAIL) , but it got blown right after I replaced maybe within a second .
So :
1. Both left and right taillights not working
2. Both left and right tag rights not working .
Everything else works.

We’ll kind of works I mean it’s a separate thing with the AC not working(blowing hot air) while I’m at a stop sign or parked in Florida weather ‍♂️.
While you drive the AC does work ok blowing cold air.
But the tail lights are the biggest issues got stopped by the police ‍♂️ already and got warning ⚠️ hopefully not getting any fines
Thank you all so much for suggestions.

 

Any competent repair garage should be able to find and fix a problem with a tail light circuit; this isn’t a problem for which a Toyota dealer would have any special tools or skills.

Before you changed the bulbs for the license plate lights, which lights weren’t working?

The fact that the replacement fuse blew immediately suggests a short circuit in one of the light assemblies (headlight assemblies, with parking and marker lights; rear combination light assemblies; or license plate light assemblies), or in the wiring from the load side of the TAIL fuse to the light assemblies. The Electrical Wiring Diagram (more info) shows the circuit and all the junction and wire-to-wire connectors.