im about to put a set of s5 taillights on my s4 and was wondering if the s5 bulb harness will plug into the s4 chassis wiring and work correctly. anyone ever try this?

 

It is plug and play.
The S4 harness though on the s5 tails will fit too,but I noticed that one bulb connector insert is a bit different than the ones that the s5 uses.
So in Short,use the S5 Tail light harness and plug it into the Car's harness and you are good to go.

 

SWEET! thats what i wanted to hear! thank you

 

What Styx said as you may have to Dremel a nub off some of the S4 sockets to get them to fit into the S5 housings but its an easy do.

 

you might also have to cut a bit of sheet metal out of the back of the car to get your lights to sit flush. it's a small piece near the reverse lights iirc, you can search and find out more about this.

 

Oh ya,I forgot that..a little piece of metal on the inside where the bulbs sit will need to be cut.(2nd bulb towards the licence plate I believe..been awhile since I did a Conversion),You can do it with a Dremel or a pair of snips,depending on how picky you are.
Really you won't see it once the lights are installed and you are doing 80 MPH!.haha..(as it is on the inside between the tail light assembly and the Rear Spare tire carpet!).
I hope that helps ya..