Turn Signal acting funny

Not real sure what is going on but when the truck is off and the brake is applied, in the dash the left turn signal lights illuminates. When the truck is on and I put the left turn signal light on all the lights on the truck blink but when I press on brake it stops. I have replaced all the bulbs and checked all the fuses but I still have no idea what is going on with this truck. Can anyone help!!

Last time I had this happen it was on my '82 F350. all the lights WORKED, but when I'd hit the brake, that inside turn indicator would light up. Turns out I had a GROUND failure on my front turn lamp. (can happen on the back too). Since the lamp was plastic, the light socket was plastic and the world as we knew it was turning to plastic, they came up with this great idean to ground an 1157 lamp... use a tiny little strip of ferrous metal to contact the lamp base inside the socket. THIS Rusted. since it rusted, it fell apart, and while it seemed obvious to me WHAT had happenned, I had to test my theory and jimmied a little strip of tin I snipped off some scrap into the void left by the old piece, and made contact with the ground in the plug. Viola! my little lamp buddy inside the truck stayed away and I made the trip to town about 3 weeks later to get a socket and do it right:)

If you get a chance read my post 01 supercrew only the best will know im having kinda the same prob. After checking all fuses when i pull out the fuse for dimmer it stops also unplug dimmer switch same thing will let you know what i find.

BTW... its important to note that just because a bulb LIGHTS doesn't mean its working properly. many times the filament will drop and "cross" with another filament in the bulb, effectively lighting the other filament. usually anytime your inside turnsignal doohickeys behave badly, its the bulb or the ground.

Thank you. I am gonna see if that is the trick. On my truck though all the wires and the ground are inside a plactic box. I have a 97 F250 and the have made everything more difficult to get too. I even took all the bulbs out of the truck and the turn signal still lit up inside the dash. I am so lost when it comes to what is going on with this truck!

Thank you. I am gonna see if that is the trick. On my truck though all the wires and the ground are inside a plactic box. I have a 97 F250 and the have made everything more difficult to get too. I even took all the bulbs out of the truck and the turn signal still lit up inside the dash. I am so lost when it comes to what is going on with this truck!

With that info (removed all bulbs, problem still there) I'm gonna speculate that you have a bad turn signal switch. I've seen many trucks, ford included, that had electrical issues pertaining to turn signals, brake, and parking lights. Most often it was a ground or switch problem, thing about ground problems is that if you remove all the bulbs you eliminate the bad ground. That just leaves the turn signal switch which appears to be bad in your case (brake switch lights up turn signal indicator).

I'd bet on a ground being bad.

You Have A Bad Ground Somewhere! Hard To Find But Easy To Fix...

I love these bad ground on the 82 Fords bla bla bla. Things have changed from 82 to 2000. More than likely it's the multifunction switch. Do a search on it, you'll see the results...

Gonna lock this thread. This is almost 4 years old. Please look at original date before posting.