Turn signal lights on drivers side very weak

[p7387]

Hello
Vehicle in question - 87 r10 2wd short fleet

The rear and front turn signal bulbs on the drivers side have a very, very weak blink, however the side directional on the same side blinks normally. Additionally when the turn signal lever is in the off/neutral position these same bulbs on the drivers side burn much brighter than the ones on the passenger side.

All the signal bulbs on the passenger side are functioning normally.
Any tips would be appreciated.

Thanks

[VileZambonie]

Make sure you are using the same bulb numbers on each side, clean the sockets and grounds.

[75gmck25]

x2 - Its usually sockets and grounds.  IIRC, each light has small ground wire that needs to be firmly screwed down to bare metal near the socket.  You can also buy a spray can of Deoxit to clean off the terminals inside the sockets.  A pencil eraser works fairly well to clean the sockets inside, but the Deoxit seems to work better on old corrosion.

There is also a ground wire on the radiator support for each headlight, and a white, large gauge ground wire to the frame in the back of the truck up behind the middle of the rear bumper.

The other very important ground is the black wire up under the instrument panel.   It may be grounded to the emergency brake mechanism, or to a ground bar under the dash.  If that ground wire is broken it will cause multiple issues with the instrument panel lights.

Bruce