LED light

I am replacing a 20 w small fixture with an 8.5 led. The led is connected to the electricity but will not come on. I put the old 20 w back and it works.
Does the led have different power requirements the the 25 w.
The box is the new led and small is the 25 w.

 

If the 25 watt fixture used 120 volts as does the new one, I would return the defective LED fixture.

On the other hand, if that is a 12 volt halogen bulb, then there is a transformer in line. The LED fixture would not be expected to work when powered via the transformer. Is there a label on the old fixture?

There are bipin LED replacements made to plug in instead of a 12 volt halogen bulb.

 

You need to check the voltage requirements of each of the two. If they are the same, it should work. If not, you may have blown the LED unit, or there's not enough voltage to make it work. Some bulbs only work on acv, some can work on either acv or dcv. Some are designed to run on 12v, 24v, or 120v. Without knowing how your system is currently setup, there's no way to tell why it doesn't work.

If the circuit is on a dimmer, some require a minimum load. Some will work with incandescents, some don't like LEDs. If it's just an on/off switch, disregard this.

 

That looks to be a Satco S29056. If so it is 120v and dimmable. So both those could be ruled out and something is either messed up in how you are wiring the unit or the unit is defective.