hooking up led

LED+ to constant +12V LED- to IGN +12V

my LED only has a positive and a negative..doesent it need ground if i hook up one side to + constant and - to ignition +?

The way it woks is the LED GNDs thru the Ignition in the OFF (or ACC loads on ACC & IGN) position. When IGN (or ACC) goes to 12V, there is zero or <1 volts across the LED hence it extinguishes. No need for a relay, but a relay should be an SPDT aka 5-pin relay with 85 & LED- to GND, 86 to IGN, 30 to fused +12V or IGN (or ACC) & 87a to LED+. Hence the relay switches off to light the LED (otherwise you'd be using a relay that drains typically 40-200mA for a max 20mA load and draining the battery far worse). Interchanging 87a & 30 does not matter. I often connect the output loads from 30 and the power source +12V to 87a or 87a. That means there is no naked +12V 87a or 87 in either state - ie deenergised (its most common status) or energised. That saves fitting insulation (an unused spade) on 87 or 87a.

so i dont need a relay for led but should i still use a fuse on both sides of led and i was gonna tap into radio harness under dash for the power wires should that be good and led wont drain battery?

No, you don't need a relay. And you only ever need a fuse on one side of a load. For LEDs it's in the +12V supply. but it's only to protect the wiring because no fuse will protect a LED. Of course the LED will drain (discharge the battery) - it is an electrical load. But a 20mA LED should take several days to drain a battery enough to effect cranking, and a flashing LED should take less. Most alarms etc take over 40mA. A typical 30A relay takes over 200mA.   

i hooked up LED as you said and works great..thanks for info i apreciate it...i connected positive side of LED into my positive radio wire and the negative side of LED into my radio switched positive.this is a good location and i wont have any battery drain except for the blinking led correct?

It should only add the drain that the LED uses. Only on some circuits could extra drain occur - eg, if for a modern HU, LED+ to Const and LED- to IGN and if there is no IGN load to keep the LED- grounded with IGN off.