I'm having problems when I try to put my fan on high to blow the air sometimes it wont go on high. Why does it do this?

So what happens instead? Does the blower motor quit altogether?

In past years, if the blower motor worked on all speed settings _except_ HIGH, the problem was usually that an in-line wiring connector under the hood was melted. This wiring served the high-speed bypass relay, which provided full power to the blower motor when set on HIGH. (The lower speeds ran through the resistor pack as controlled by the dashboard switch; the high speed simply closed a relay.)

The relay was mounted on the firewall or the evaporator housing near the right-side hood hinge, and following the fat 10-gauge wire back towards the engine would lead you to the melted connector. It would look fine on the outside, but if you pried it apart you'd find it melted internally. Splicing around it would fix the problem and restore the high-speed blower setting.

Having said all that, I didn't think cars of the 1990s still had that problem, but you might want to take a look and see what you find. I'm assuming that you car does have the manual A/C controls and fan switch, not the all-electronic computerized climate control.

it will not work on high but all the other options it will work fine.

Do you have electronic climate control?