Toyota Prius Trunk Bulb Size

The Toyota Prius trunk utilizes 12961, DE3423, and 194 bulb sizes for the interior lighting components located within the rear cargo area. Available data for the specified vehicle covers the period from 2001 through 2018.

The year-by-year compatibility chart below provides a quick reference to verify the correct bulb size for your vehicle.

Bulb Size by Year Range

Years	Bulb Size
2016-2018	12961
2015	12961 (From 05/2015)
2015	DE3423 (To 05/2015)
2004-2014	DE3423
2001-2003	194

Bulb Specifications

Description	Bulb Size
Philips part number. Miniature wedge bulb (T10) with W2.1x9.5d base. 12V, 5W.	12961
ANSI standard (US & Canada). Festoon bulb, 41mm length, end-cap contacts. 12V.	DE3423
ANSI standard (US & Canada). Miniature wedge bulb (T10). 12V, 3.78W.	194

Other Locations

Additional Notes

The Toyota Prius trunk bulb specifications cover three distinct bulb types across the 2001-2018 model range: the 194, DE3423, and 12961.
The 194 is an ANSI-standard miniature wedge bulb operating at 12V and 3.78W, used in the Toyota Prius for the 2001-2003 model years.
The DE3423 is an ANSI-standard festoon bulb with a 41mm length and end-cap contacts, operating at 12V. Festoon bulbs seat horizontally between two spring-loaded contact points rather than inserting into a socket, which makes them physically incompatible with wedge-base housings.
The 12961 is a Philips part number for a miniature wedge bulb in the T10 form factor, fitted with a W2.1x9.5d base and rated at 12V and 5W.
Both the 194 and the 12961 share the T10 wedge form factor, though they differ in wattage. The 194 is rated at 3.78W while the 12961 is rated at 5W, and substituting one for the other without confirming socket and circuit compatibility is not advisable.
The 2015 Toyota Prius requires two different trunk bulbs depending on production date. Units produced up to May 2015 use the DE3423 festoon bulb, while those produced from May 2015 onward use the 12961 wedge bulb. These two types are not interchangeable due to their different base designs.
The DE3423 festoon bulb was the trunk bulb for the 2004-2014 model years, representing the longest continuous application of a single bulb type in these specifications.
The 12961 designation is a Philips-specific part number rather than an ANSI industry standard, meaning equivalent bulbs from other manufacturers are typically cross-referenced by their T10 W2.1x9.5d base type and 12V/5W rating rather than by the 12961 number itself.