View Full Version : turn signals stop working...

04-23-2011, 09:44 AM
turn signals stop working when buddy turns his headlights on in his 1981 Chev Pickup 4x4. When you put the 4 way flashers on the turn signal lights in dash light up but stop working when head lights turned on. Wiring appears good to tail lights and we put new headlight switch in. Column turn signal lever engages ok but we are thinking to pull column apart next. Any help would be great!

04-25-2011, 09:03 PM
Check the ground on the fire wall and replace the flasher module

04-26-2011, 10:25 AM
Seems like all grounds good especially since we just did engine re&re. I'll loosen grounds and clean on rad support and firewall. I have diagnosed problem to front turn signals. I took all bulbs out and disconnected rear tailight plug on firewall. I turn headlights on and then turn signals. As soon as I put a bulb in one of the front turn signal sockets the bulb glows dim and signals come to a halt and lights in cluster just glow. One fuse under dash says "ts ctly" what does that mean? Seems like that is the running lights fuse. Next step is to look at wires in steering column. Dash and cluster all pulled out and cleaned and still no worky. I'm trying to fuigure out how the headlight circuit ties into signal light circuit. Theres got to be a bad ground or short somewhere. Today will be day 2 trying to fix it, lol. Replaced flasher and seems to work better.

04-26-2011, 12:33 PM
do you have atilt column , if so is it losse , i have had that problem with losse tilt and wiggley turn signal , i replaced column and everything is good, hope this helps :)

04-26-2011, 07:18 PM
most people dont use their turn signals anyways

04-27-2011, 10:04 AM
Well after a second day I finally changed front turn signal holders (for bulb) on both sides and walla problem solved. Front bumper has turn signals built into bumper and so corrosion big time. After seeing "green" in each socket I just said lets strip a couple off one of the other trucks. We did pull instrument cluster and looked like a rat had been living behind it so we cleaned that out and also luckily did not pull column completely apart. I did some research on the net and learned that the reason the turn signals work with headlights off is because the turn signal circuit uses the running lights circuit as a "phantom ground" until you actually turn on the running lights\taillights\headlights. Once the running lights are on, the "phantom ground " is gone and turn signals dont work. I also learned another solution may be a poor alternator or alternator connections. Once headlights are on their can be insufficient current to power up turn signal flasher unit. You can actually buy low current turn signal flashers to plug into your fuse block. So hope this thread helps others in future!

04-27-2011, 06:27 PM