Where is the Flasher Located in a 1990 Cadillac SEVILLE?

Turn Signal Lamps
The TSIG/HAZ fuse in the rear fuse block supplies battery positive voltage to the flasher module. The module is part of the hazard switch assembly. The flasher module has ground at G201. The turn signal lamps may only be activated with the ignition switch in the ON or START position. The IGN-1 fuse in the rear fuse block supplies battery positive voltage to the turn signal switch. When the turn signal switch is placed in either the left or right position, current flows from the turn signal switch assembly to the flasher module. The flasher module then sends an on-off voltage signal to either the left or right turn signals and their instrument cluster (IPC) indicator. When the hazard switch is pressed, the switch contacts are close and the turn signal/hazard flasher module hazard input is grounded. In response to this input, the turn signal/hazard flasher module supplies battery positive voltage in an on and off flashing pattern to all the turn signal lamps. This also activates both turn signal indicators. When a THEFT is occurring, the DIM grounds the turn signal/hazard flasher module hazard input. The left turn signals have ground at G401 and at G402. The right turn signals have ground at G401.

Could be several things. But first make sure that the turn signal flasher is good. It is different than the 4 way/emergency flasher.

Left side of the steering column. Remove the kick panel, the knee panel, and a metal plate covering the steering column
you will find the turn signal flasher relay well hidden, mounted with a clip on the back side of the left non-removable knee panel, behind the lip edge of the panel, hope you have a good flashlight, it is black and can not be seen if you do not know that it is there.

1. The flasher is hidden under the left (drivers) side of the dash, in the vicinity of the steering column.

it is located down under rh side of dash . below glove box abd is usually the third fuse in the bow

I can tell you exactly where the turn signal flasher relay is located if you wish.

check bulbs

Under the dash on the driver's side, way up inside.

I do Believe that it is Under the Dash on the Driver side Fuse Panel at the Top of the Fuse Panel.

Turn signal flasher module is behind dash left of steering column near chime module. I have a 94 Seville and I had that same problem you need a Turn Signal Flasher Moduel, I forgot the proper term for it but I had to get mine replaced too. When I hit the signals to turn the side light would come on but the signal light wouldn't. Its a little box you get from Cadillac it only cost like $20 - $25 and you get it installed and trust. It'll work again. I just got mine done this week and my car now has turn signals again.