It was red before until I got a transmission flush, not sure if that actually affects that. Now it's red again. I had an oil change less than 3k miles ago, tranny flush about 10k miles ago. Everything seems to be working fine, no overheating. All liquids are at the correct level.

I installed a SRI about 500 miles ago, but nothing came up then. Any possibilities?

 

Push your key into the slot next to the red maintenance indicator. This will reset it to green. In approximately 7,500 mi the indicator will again switch to red as a friendly reminder to change your oil.

 

That particular light is just a timer based on time and mileage. It doesn't actually sense and detect problems. You (or the technician doing the work) have to reset it manually after the oil change or other maintenance is done. The car's owner's manual should explain more about it.

 

if it turns yellow what does that mean? Either it was yellow the whole time, it changed from red to yellow, or I'm partially colorblind.

 

Yeah, as I remember, it progresses from green to yellow and finally to red at the 7,500 mi mark.

 

Correct. Reset the switch with your ignition key - it turns to green. From 0 to 7500 miles, it will gradually switch from green, to yellow, and finally to red. Its there to remind you of oil changes and nothing else.