I am having a problem reagarding painting US vehicles in ODS and OIF. I tried using desert yellow. It was too dark. Tried using light sand, it was a little brown. Can anyone tell me what color to use to get that armor color similar to the preview models on boxes of Tamiya? I think it is some kind of yellowish paint.

I believe Tamiya's Desert Yellow is intended for German armor... For a color more like US Desert Sand, try mixing White (flat or gloss) with Dark Yellow till it looks "right" - I didn't use exact proportions, but I estimate about a 50/50 or 60/40 mix would do the trick....

I've found that Tamiya buff works great, you can lighten or darken it to your taste. Now for modern British Armor I used Acryl Model Master British Armor Sand. I've found this to be a great match to photos I have.

Tanks Out
Andy

Buff does look a little too light. Might as well give it a try.

Best color for OIF US Forces is Testors 2136 US Army/Marines Gulf Armor Sand for a out of the bottle color.

I use Poly Scale US Desert Storm Sand, has the "right out of the bottle match", at least to me. This color is hard to get right, every picture you see, the color will look different. Some look slightly pink, others really white, some brown. From my own personal experience, the poly scale color matched right up with my paint chips. For what it is worth, it was a USMC Amtrac with an desert scheme, from the middle 90's. Hope it helps.

Model Masters makes a paint called "USMC/US Army Desert -----" Can't remember all of it.
(must be a sign of old age) Goes on straight from the bottle to your AFV and its the "right " color.