I bought some led bus for my tail lights. When i installed them they would not light up. I installed the old bulbs and they work. That made me believe that the LESs where defective but when I connect them directly to a battery they light up. Has anyone else had this problem. If so how did you fix it. Thanks

 

Not enough current going to them..measure the voltage at bulb sockets

 

I wouldn't think it's a voltage issue. I thought LEDs use less amperage than a standard bulb? Maybe I'm wrong. Check to see your using the right bulbs. There's dual filament and single. I think the brake lights and turn signals are all dual, and the reverse light is the only single.

 

It's voltage he's looking for, not current. Make sure the **** are the same on the bulb bases, if they are then check the voltage at the sockets. It might be too low for the LED bulbs to light, but enough to light up the incandescents.

 

Check the polarity. The "D" in LED is for "diode". They only allow current to pass (and lght up) in one direction.

 

Well i got the chance to check the voltage at the socket today and i have 9.6v at the socket with the car not running but the current is correctly polarized. I think that might be a bit low. I then hooked up the bulb directly to the battery and got a readout of 2.5v. Any ideas where to go from here I'm at a loss cause I rarely do any electrical work. Thanks

 

how much is the voltage when the car is on? LED require a certain amount of voltage before they light up.. if they only light up with the battery then you need a minimun of 12v reaching the socket.

 

A close-up pic of the bulb would help determine if you might not be getting good contact at the socket terminals or if something can be done to reverse polarity as noted by TonyD89.

 

this


they are polarity specific- try taking them out and reverse them in the plug

but it would seem odd you installed every single one backwards

 

Sometimes i wonder if you guys hate reading...

 

yes most of us hate reading

my car was parked since October and I went to start it up last week, battery tender must have **** the bed at some point during that time. I had just a bit over a dead battery worth and my LED lights still worked so Im not sure what the issue is with his lights except that they might not be seating properly in the socket I dont think its a voltage issue