check gauges light

I noticed today when I started my 96 Bravada that the check gauges light was coming on and off. When I put it in gear and began driving it went out, but when I stopped at a light it came back on. I'm not sure and was wondering what could cause it to do that? I don't know if it's connected or not, but the oil pressure gauge was showing in the red then came up.

That light comes on for that reason, to check your gauges. Low fuel, low oil pressure, low alternator output, ect...If your oil pressure gauge was in the red when the light came on, then that's why. Check your oil level. If the oil pressure keeps acting up, you may have a gauge, oil pressure sensor or an actual oil pressure problem.

From what I read elsewhere I am leaning towards the idea it could be the oil pressure sending unit

That's where I'd start also, fairly cheap and usually not hard to replace.