i just picked up my S4, and the old owner of the car put S5 tails in it (he gave me the stock s4 tails, center piece, and bulbs harness' for the s4 tails)

whenever i hit the brakes, the "brake" light lights up in the idiot cluster...and i have been told that the passanger tail light lights up brighter than the driver side tail light.

i have looked at all of the wiring, and the fuses and everything seems to be good.

anyone have any idea's on what i could do?

 

mine does the same thing but my bulbs/lights are fine, I just always thought it was funny.

 

Never heard of this before. My S5 lights (w/ S5 bulb harness) work just fine. No odd behavior at all.

 

you have a Bad bulb,or you replaced a Bulb with the Wrong one.
Did you use the S5 harness on the Install or did you keep the s4 harness?
Check the Bulbs..make sure they are the right ones.

 

i didnt do the install, i purchased the car last sat and have been spending all my free time after work replacing fluid's, the driveshaft, the turbo back exhaust, cleaning, and making the car as close to perfect that i can.

thanks for the bulb idea....i bet he put wrong bulbs in on the passanger side...

 

Also, could be low brake fluid. check it.

 

the harnesses are the same between s4 and s5...

 

i checked it today, its not low.

 

ok, i was just saying, he gave me the s4 tails that came out of the car with the harness' still in them.

he used the s5 harness' that he purchased with the s5 tails and center piece.

i am thinking he had to replace bulbs for some reason and the bulbs on the passenger side are different somehow which is why they light up brighter when hitting the brakes.maybe ill just buy all new bulbs for the tails and see what happens.

 

there are two possible ways to have the bulbs in.

one way lights up the brighter filament on braking, and the dimmer filament on parking lights


the bulbs could be put in the wrong way where they are switched. not familiar with the way the s4's "brake" light works, but it could be seeing a low current draw from one light, and alerting you.

 

i had the same thing before, i had it with the S4 and S5 lights. its stopped though...

 

I had a post a couple years back about this. I have same problem, S5 tails in an S4 and when i have brakes on the "Brake" light warning comes on (the one that tells you when you have a bad bulb, not the ebrake light). I didn't do the tail light swap. when i posted about it nobody had ever heard of this problem. apparently it is more common now lol Anyway, i found some corrosion on a couple of the bulb sockets, so i cleaned them up and the problem went away for few months, but then returned. I haven't gotten around to investigating it any further, but would like to hear any suggestions.

 

fixed it!

turns out the old owner put ricer style LED bulb's in the tail lights instead of the factory style glass ones.

pulled the bulbs out of the S4 harness' and put them into the S5 lights....works like it should.