Chevy truck turn signal problem

Our son has a 97 Chevy C/K pickup truck and told me about a problem that I thought was easy to solve, and we tried, but it wasn’t. The driver’s side front turn signal flashes fast. I checked the rear lights on that side and the turn signal wasn’t working at all, let alone the tail lights, so I replaced the bulbs. They’re the kind with the 2 filaments. I noticed the old bulbs were covered with some nasty yellow corrosion. Now the turn signal problem is the same and still no brake light on that side but he has tail lights at night. I tried to clean up the corrosion in the circuit board (none on the bottom light, which is the reverse light) with a neighbor’s wire brush but it didn’t change anything, so he suggested I change the circuit board. Any other ideas or is he right?

Often this

is the source of the problem.

I agree with Rod Knox. Very common problem on these trucks.

By the way the yellow corrosion was most likely the factory dielectric grease. Its looks pretty bad when dried out. When replacing the circuit board make you use dielectric grease on all connections and bulbs.

Thanks guys. I’ll try it this weekend.

I have the exact same problem. did the new circuit boards fix it?

While the rear running lights might be ok it still doesn’t help because the turn signal light uses the other filament in the lamp along with the brake light. It does mean though the ground for the light is ok as they share the common ground. Does the brake light for that side work? If that doesn’t work either then look for the problem to be under the dash possibly or in a connector between the dash and the rear lights. The problem could be with the circuit board also.

One trick you could use is to apply power to the proper input wire of the circuit board and see it things work there okay. If it does you know the problem back towards the dash.