Where is the brake light relay switch located on my s60 volvo 2004?

Check the brake light switch. It is located at the top of the brake pedal under the dash. It seems as if it's stuck. Good Luck Friend.

usually on the fuse box block.

Crankshaft sensor on the transmission is faulty

http://www.autozone.com/autozone/parts/Duralast-Stoplight-Switch/2001-Volvo-V70/_/N-jetkaZ9cias?itemIdentifier=365252_0_0_

There is a switch located above the brake pedal, this switch can be adjusted. It can be hard to see, climb under the dash, and look up towards the steering column, check the switch for proper operation.

there should be a a button on the shifter cover to push and hold to release shifter of theres a small cover at the same location that you remove and insert your key to shift,also check to see if your brake light are working,the shift release get power from brake switch power,check your fuses also.

check the brake switch on the brake pedal under the dash board

the relay is located by the fuse box and i think it might be a switch problem

I had a similar issue and I replaced all the bulbs and that fixed my issue.

My 2001 S60 just had the same issue. The "check brake light" error message on the dash and the brake lights not illuminating ( the upper center glass brake light would). I found that both bulbs had failed which I replaced. The fuse was okay but still the error message was found on the dash when the brake peddle was pressed. I purchasing a dealer $30.00 brake light relay and the problem is fixed. However, there isn't a diagram anywhere that shows which relay was for the brake light relay. In my 2001 S60, the relay is in the trunk, beneath the driver side removable upholstered cover. The relay panel has ~ 10ea of the same relays and a few other odd sizes. There is a vertical column of relays on the left and right. I found the brake light relay is located between two other relays on the upper right column. It was difficult to reach due to a larger relay on it’s right.