I recently purchased a used 2015 Toyota Sienna XLE, which is fantastic overall, but I’m encountering a perplexing issue with the interior lighting. Specifically, none of the interior dome or courtesy lights are functioning. Whether it’s day or night, with the doors locked or unlocked, or using the manual switches on the headliner, these lights remain off. I’ve even checked the instrument panel dimmer, but no luck. Essentially, the dome lights, including those in the 3rd row and elsewhere in the interior, simply refuse to turn on under any circumstances.
Interestingly, all other interior lights within the Toyota Sienna’s cabin seem to be working correctly. The radio, air conditioning controls, door switches, and instrument cluster are all illuminated as expected. The headlights and taillights also function properly. Although, I did notice that the headlights don’t activate when unlocking the van at night, which I’m unsure if it’s a standard feature for this model, as my previous Honda did have that functionality.
In an attempt to resolve this Toyota Sienna Interior lighting problem, I checked several fuses that seemed relevant. I visually inspected the following fuses, and while none appeared to be blown, I did not formally test or replace them: ECU-IG1 (10A), ECU-ACC (10A), OBD (7.5A), ECU-B (10A), and Dome (7.5A).
Furthermore, I attempted a relay swap to rule out a faulty relay. I exchanged the DOME relay with the ignition relay, as they share the same part number and color. However, this relay swap made no difference; the interior dome lights still did not illuminate.
To further diagnose the issue, I connected a Techstream diagnostic tool to the Sienna. The scan revealed no current or previous fault codes related to the body electrical system. Techstream appeared to be functioning correctly, as I successfully performed an active test on the Daytime Running Lights (DRLs). However, when I attempted the active test specifically for the interior lights using Techstream, again, nothing happened – the lights remained off.
At this point, I’m seeking advice and wondering if I might be overlooking something obvious in troubleshooting this Toyota Sienna interior dome light problem. Any insights or suggestions on what to check next would be greatly appreciated.
