Where does the flasher relay go in a 2003 Cadillac Devils

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.

https://www.justanswer.com/car/16er8-turn-signal-relay-located-dash.html

and contradicted here (different model)

https://www.fixya.com/cars/t26714601-location_flasher_relay_2008_cadillac_xlr

Check Fuse 30 under the back seat

https://www.autogenius.info/cadillac-deville-2003-2004-fuse-box-diagram/

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Modern vehicles don't have a flasher unit, they work from a signal from the Body Control Module. The article below is for a 1999 model and says with a picture

Okay. It is located under the dash on the driver side of the vehicle right next to the steering column.

https://www.justanswer.com/car/16er8-turn-signal-relay-located-dash.html

and

https://www.google.com/search?q=%222004+Cadillac+Deville%22.+turn+signal+flasher+location&tbm=isch&ved=2ahUKEwi-t5mAvqj2AhX-gHIEHcFLA_EQ2-cCegQIABAA&oq=%222004+Cadillac+Deville%22.+turn+signal+flasher+location&gs_lcp=CgNpbWcQAzoHCCMQ7wMQJ1CxEliGU2D8amgAcAB4AIABf4gBqAKSAQMyLjGYAQCgAQGqAQtnd3Mtd2l6LWltZ8ABAQ&sclient=img&ei=zPAfYr6hBv6BytMPwZeNiA8&bih=937&biw=1920&rlz=1C1QJDB_enCA643CA644

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Flasher/Turn signal Relay is part of the Hazard warning switch.
Remove Instrument panel Trim. Then Remove the hazard warning switch from the center air outlet.


I’m happy to assist further over the phone at https://www.6ya.com/expert/uttamjeet_2f3adc18600f8ede

this schematic shows the relay location , it is passenger side , have to remove the cover/door and the cover/door should have the different relay position on it , if the indicators are still operating turn them on and touch each relay and yiu will feel the flasher relay "clicking",hope this help

You have to remove the whole assembly from spindle

On Cadillac Deville, the Flasher is located:
- Hazard flasher: Front seating area, driver side, under dash, mounted on passenger side of steering column
- Turn signal: Front seating area, driver side, under dash, mounted on passenger side of steering column

1. Remove the necessary sound insulator panel(s) from under the instrument panel.
   
2. Remove the flasher from the retaining clip and disconnect the wiring connector.

To install:

1. Connect the wiring connector to the new flasher and install the flasher in the retaining clip.
   
2. Install the sound insulator panel(s).

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Try replacing the flasher relay.

To detect this flasher; turn on the turn signal and listen for the flasher in the fuse box, with your finger on the top of the flasher relay you will be able to feel it clicking inside.

it is in the dash maybe leftside sterring colum

Under the Dash on the Drivers Side is a Fuse Panel. At the Top of this Panel is the Flasher Relay. Should be the one on the Left I Do Believe.