Hey there, so I have a 97 s10 blazer with the 4.3 vortex in it its the four door model with a center floor automatic shifter transmission a month or so ago I had a pro set up my trailer light after mine were cut well it blow the flasher unit and I replaced it and had my mechanic look at it and he fixed the wiring well a couple weeks ago I hauled a trailer and when I got home (after the lights worked fine). The lights weren't work so I went and got a new flasher unit and that didn't help I checked my fuses all were fine my bulbs are good what could have happen????

 

Do your 4-ways work? How about your lower brake lights?

 

What is the four way and all my lights work encluding my hazzards

 

4-ways = hazards.

What lights are not working specifically? Only the trailer lights? Or the turn signals on both the trailer and truck? Or something different?

 

I have no blinker on the trailer or the truck but I do have hazzards so I no the bulbs are good and I know there must be a connection

 

Ok. So using your terms, blinker == turn signals.

The turn signal flasher module is separate from the hazard flasher module, however they are located side by side and are identical. Which one did you replace?

If your back up lights work, then the 'TURN B/U' fuse is still intact.

 

Back up lights work and I changed out the flasher fuse for the blinkers it was clearly marked on it and the hazzard fuse is fine

 

Swap the hazard flasher module and the turn signal flasher module.

All signs point to a faulty turn signal flasher module.

Do the turn signals work properly with the trailer unhooked?

 

Did that and bought a new one no difference

 

I'll ask again because it seems you missed it:

Do the turn signals work properly with the trailer unhooked?

If the signals work properly, then your flasher is not made for the additional load that trailer lights put on it and you need a HD flasher.

If they do not work properly, then you have to dig into the wiring because everything else is working properly.