I just got my s5 tails and I the bulbs were okay but not bright enough. but I noticed that when I stepped on the brake with the old s5 bulbs in the brake idiot light would come on, which was kinda cool. but at night I noticed the bulbs weren't good enough so I switched to my known working bulbs off the old s4 tail lights and now when I step on the brake, the clock dims and the cluster lights and HVAC controls light up.

when I let my foot off the brake the clock light goes back to normal, and the cluster/HVAC lights turn off again (unless Its night and I have the lights on)

I can do it when the car is off too

 

Anyone?

 

see u pee sodler joints

 

bad grounds. Look up all the grounds in the wiring diagram and clean them up really well.

 

Sounds almost like the shitty wiring in MY car. D:

 

I've done that already, to get rid of the dreaded hesitation.

 

The idiot lights come on at really low voltage. Your alternator isn't supplying enough power at the given stopping rpm to power the lights.

The tail lights shouldn't change it that much, but remember, the alternator was upgraded several amps between s4 and s5. (from 60-80?)

 

Check the bulbs in the tail lights, you might have a single filiment bulb in a dual filiment socket. The single contact point on the single filiment bulb will rest on the two dual contact points, that will make the driving lights come on when the brakes are pressed.

 

well the driving lights dont come on, the cluster and hvac light up.

 

Thats weird, I was confident in that being the problem. If I come up with any more ideas I'll let you know.

 

I am gonna check the bulbs though, or just spend 4 bucks and get new ones heh.

I dont get to see my car for 2 weeks though since of the snow and crap its stuck in the garage.