Blown Taillight

I have replaced both of mine, the left went first at about 30k and the right went last month at 57k.

 

<div class='quotetop'>QUOTE(seasalsa @ Nov 22 2007, 11:50 AM) [snapback]542963[/snapback]</div>

My left too went out at about 30k. I haven't yet reached 50k, but I am prepared with the second bulb from the pack. Thankfully it is a stupidly easy fix.

AS ADVANCED AS THE PRIUS IS, I'M SURPRISED TOYOTA DID NOT INCLUDE A WARNING SYSTEM FOR A BURNT OUT BULB. <_< Don't most cars nowadays have that warning system?

 

My 1990 Camry had a blown globe warning system.

 

funny, toyota is moving away from the blown-bulb reminder system. it sucks from the customer perspective until there's a problem with the reminder system... once DH spent 3 days rewiring a 3g camry that someone tried to rewire to bypass that system, it was a real mess.

 

My left brake light is out but my right one works. I checked the fuses and the three bulbs I could get out of the tail light assembly from the back side. They are all three regular filament bulbs. Since none of the three come on when the brakes are applied and since I know that the brake light is a LED bulb (comes on instantly as opposed to a filament bulb that needs to heat up - you can see the difference) and I could see two small wires coming out of the wiring harness and leading into the tail light assembly, I took the tail light assembly out of the car.
Looks to me that I will need to replace the whole tail light assembly to replace the LED brake light and the Toyota parts guy just told me they sell for something like $225!
Anyone have a less expensive fix?

 

I haven't had this problem so I don't have personal experience with the issue. Now that you have the combination light assembly out, is it possible to remove the LED brake light subassembly? If so, can you take the subassembly apart so that you can see the circuitry within?

If you can get to that point and have a digital multimeter available, you might be able to figure out why the light doesn't work. Maybe a current-limiting resistor is burnt out...

If the above is too much, then you can buy a new combination light for $138 plus shipping (MSRP of $182):
Champion ToyotaWorld

Note that this link is for 2004-2005; if you have a newer model then look up the combination light for your model year.

 

Excellent. If a bad solder joint or a burnt resistor is not obvious, then another troubleshooting technique is to apply 12VDC to the wires leading to the brake light and see how far this voltage gets on the circuit board. However, caution is required as the correct voltage polarity is important.

If an LED is reverse-biased above 3V or so, it can be destroyed. It is possible that a series diode might be included in the circuit to ensure correct voltage polarity.

Pls let us know what you determine. If you can post photos, even better!

 

I just pulled the curcuit board - it has a total of 9 resistors, 5 are 24 ohm and 4 are 6.2 ohm, and one diode. As far as I can tell with my digital multimeter, all check good.
Any suggestions on what I can check/do next?

 

Sorry Patrick, I missed your last post before sending mine.
No evidence of a bad solder joint or discolored resistor or melted contacts/plastic in the two connectors.
I hope to get some time tomorrow to apply 12 volts to the incoming contacts and see what voltage comes off the outgoing (to the LED)contacts.

 

If you are unsure about the correct battery polarity, you could just plug the disassembled light's wiring harness connector into the car's wiring harness. Then have someone press on the brake pedal while you measure the voltage with your meter. This will allow you to see which wire is positive and which wire is negative.

If you are comfortable troubleshooting the circuit board while it remains connected to the car, connect the negative test lead of your meter to the negative wire. Then probe around with the positive test lead, starting from where the positive wire attaches to the circuit board. See how the voltage changes as it passes through the various resistors. It might help if you draw a schematic diagram of the circuit board, then note the voltages that can be measured at each resistor.

At some point you may either read zero voltage, or else no change in voltage:

- The former means either that you are measuring ground potential, or that the resistor being measured is open (hence no current is flowing through it).
- The latter means that the circuit is open at some point beyond the resistor whose voltage is being measured.