How to install lower beam relay and were is it located the lower bean stopped working all fuses and bulbs ok

Solution: If both headlights aren't working, it's unlikely that a bulb is at fault. The likely cause is a fuse, headlight relay, headlight switch, dimmer switch or a wiring fault. ... Consult your owner's manual to locate the main fuse for the headlight circuit and replace that fuse with one having the same amp rating.
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Most total headlight failures are caused by a bad component like a fuse, relay, or module. Wiring problems can also cause both headlights to stop working. High beam headlights don't work or low beams don't work. The cause: A burned out bulb, or a problem with the high beam switch or relay.
https://www.lifewire.com/fix-non-working-headlights-4137021

Most total headlight failures are caused by a bad component like a fuse, relay, or module. Wiring problems can also cause both headlights to stop working. High beam headlights don't work or low beams don't work. The cause: A burned out bulb, or a problem with the high beam switch or relay
https://www.lifewire.com/fix-non-working-headlights-4137021

there is a fuse for that circuit in the fusebox lower dash if this is ok check that your getting power to the high beam wire at bulb holder if not the part of switch for high beam isn't working if are getting power check the bulb holders for warping etc as can get very hot and mishapen so that the bulb doesnt always sit on the contacts but if bothe lights out i'd think its a power supply problem

There is no low beam relay.

For Audi A4 the fuse box is located on the left side of dashboard behind a plastic cover (for left hand steering wheel vehicle). On inner face of the plastic cover you will find the fuse diagram.
First fuse on first row from left upper corner is Fuse Nr.20 = F20 (15A) - RH headlamp low beam, headlamp adjustment.
First fuse on second row from left upper corner is Fuse Nr.21 = F21 (15A) - LH headlamp low beam, headlamp adjustment.

There maybe a headlight relay under the hood, most are in a protective box. There may be a fuse also under the hood. Ck the fuse if there is one and tap the relays with you low beams set to be on. Good Luck, Ned

Yes your daytime running light just uses the headlight bulb on a lower voltage so if the headlight is not working the drl will not work as well, they are dirrectly related,,check the head light fuse,and check to make sure the bulb is good,,

Ok, locate the relay panel (probably inder the hood) and find the relay that controls the headlamps. With your headlight switch "on", pull the relay and see if your getting a hot current to the connectors in the relay panel. If it's hot, replace the relay. If no current, it's probably your headlight switch.

do your flash to pass lamps light when you pull the stalk towards you? If yes, the bulbs are ok.
Do the hig beams work?
Your headlamps have sepaerate fuses for each headlamp and you have a low beam relay and a high beam relay under the hood in the black box.
If everything is out, I suspect a bad headlamp switch.
Check car-part.com and look on page with * for cheapest price.

Your owner manual will identify fuses & relays.

PS, You did not recently instal high current bulbs did you? If yes, put originals back in.

HEADLAMPS

The voltage is supplied to the lamp switch through a fuse. This fuse is located in the central junction box in the left-hand footwell.
When the headlamps are switched on, a voltage is supplied to the high beam/low beam switch and to the low beam relay. The relay for the low beam is located in the battery junction box (BJB) in the engine compartment.
If the high beam/low beam switch is set to "low beam", then a voltage is supplied through the low beam relay to the low beam part of the headlamp assembly. The left and right-hand low beams are fused separately. The fuses are located in the battery junction box (BJB) in the engine compartment.
If the high beam/low beam switch is set to "high beam", then a voltage is supplied through the high beam relay to the high beam part of the headlamp assembly. The left and right-hand high beams are fused separately. The fuses are located in the battery junction box (BJB) in the engine compartment.

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Lamp Switch
Removal

1. CAUTION: Disconnect the battery ground cable. For additional information, refer to Section 414-01 .
   Remove the lower driver's side footwell trim.

1. Detach the lamp switch bezel.
   • Remove two screws.

1. Remove the light switch.
   • Remove three screws.
• Disconnect the electrical connector

If your car is running daytime running light system .. there is a DTR relay that goes defective and needs replacing ... I had the identical problem that was fixed with this replacement. The DTR relay is behind the glovebox.