Picked up an electronic type flasher for my upcoming LED S/T/T lamp mod. It is non-load dependent and does not have the "bulb out" alert. It is a Trico flasher and has 3 terminals, just like the one on my truck (1993 Chevy Silverado).

But I put it in and as soon as I turn on the ignition, (without hitting the turn signal), it automatically blows the fuse for the lamps. It does say something on the flasher about the input lead needing to be fused, but the circuit is allready fused (15 amp) so I think that refers to other vehicle applications.

Any ideas as to why this is happening and what I can do to fix it?

I've dealt with that type before. The 3 prongs on your truck's OEM flasher are not the same as the 3 on your new 3 prong flasher. HERE'S WHY: The 3 prongs on your truck include one for power supply (from L or R on from turn sig switch), another that goes to the load (to lights in rear), and the third is a GROUND to power the factory flasher, which is why your fuses keep blowing. Now the 3 prong aftermarket, the 3 prong are different, one is for power, other for load, and third goes to indictor on dash board usually on big trucks. YOU need to go get the regular 2 PRONG universal flasher, and it will try to plug in to your truck one of two ways. Just plug it in whichever way that allows your flashers to flash normally, and that automatically tells you that you are connected to the correct 2 prongs (power, and load). And you'll know that your not on the 3 terminal which is the ground leg for the OEM flasher. The reason aftermarket flashers don't need grounds is because they just get their power to operate in series through the current that is passing through the circuit, but this only allows the flasher to still work with a minimum of one bulb functioning, but OEM flasher has it's own ground so it will still flash (very quickly) even if all bulbs are out (to let you know something's wrong I assume?) That's just how they chose to do it I guess. So go get a 2 prong flasher, and it will only fit in one of 2 ways so it aint hard to figure out which is correct. Or you can use your ohms meter and find which terminal is the ground on the socket, and just connect your 2 prong flasher to the other 2 wires.
Hope this helps, let me know if it does, ok

Thanks alot, I will let you know how it turns out.

One question, may seem kinda dumb but I'll ask anyways: What would happen if I just ground off the center terminal that is not needed so that it doesnt make contact? I guess I could try no matter what, cause I dont think the store will let me return it.

I too, accidently bought the 3 prong one for my car. The fix for me was to make 2 little short jumper wires that were only like 2 inches long. And I hooked the jumpers on the flasher to the 2 end terminals and NOT the center one, and then I hooked the other end of the 2 jumpers, first one to the power source and the second one to the load (which wound up being one center and one end terminal of the vehicle plug- as the third end one was the ground). So I know it's possible to wire it that way. I also taped a piece of foam cushion around the new flasher since it is mounted in the steering column near the turn sig switch and was very loud. Now you can't barely even hear it click. Before, it was really loud and echo'ed inside the column which was very annoying!