naca777

I have a 1987 F-150 that has been giving me some problems with the front turn signals. The rear turn signals work just fine. I have tried to troubleshoot the problem and wanted to post here to get some feedback on if I'm going in the right direction.

I went to the front left turn signal and tested the socket itself for current while the truck was on with the turn signal flashing. Couldn't get anything to happen on the circuit tester. I then tested the main wire (green) with the circuit tester and the tester bulb blinked on and off just as it should. This makes me think the bulb socket on both sides could be bad? I have also tried new bulbs just to be sure Any ideas?

Good old Bill

Welcome to the Forum. Am thinking your procedure is on the right path, my memory with the green wire for the LH turn is in question. Regardless, if power is at the wire at the socket perhaps the ground is at fault , especially if both fronts are inop.

naca777

Thanks Bill!

I'm not sure if this is the correct way to test the ground but I did try cutting the black wire (I think black is the ground and brown is the steady power). I clipped the ground clip on the tester to the black wire and then tested the green wire and still got the tester to blink. Is this an accurate test?

Just call me Sean

iTrader: (1)

Do the front parking lights work?

naca777

Hey Sean,

Thanks for the reply. Only lights that currently work in the front are the headlights.

Just call me Sean

iTrader: (1)

Then I also would have to say a ground problem. You can take the ground wire at one of the front bulb sockets and ground it anywhere to see if the lights start working. You can even leave it grounded there to fix the problem if they do start working.

naca777

Just wanted to update this thread to let everyone know I was able to fix the problem. Tried testing the ground wire by grounding it somewhere else on the truck and still did not get any response. So I went ahead and replaced the bulb sockets and everything immediately worked. Turns out the sockets deteriorated on the inside. Thanks for everyones help.