gazi001

You got it. I had same issue.

trhs75

Isn't that amazing? I mean, who would have ever guessed that would be the problem. If it hadn't been for the advice on this board, I might have gone crazy from the noise and jumped out the
window!!

milker

After reading some of the answers, I noticed my reservoir was almost to the top, so I thought that the fluid may be getting into the top of the sensor, I slid the robber cap off the sensor a little to see the top of the sensor, I sprayed the top of the sensor where the wires go into the sensor with brake cleaner and waited till it was dry, I sucked some of the fluid out of the reservoir with paper towel and left it on the fill line. Put everything back on and no more light, it took about 5 minutes. Hope this help someone save $100 on a new sensor.

salimshah

Were you over the max line? And has the fluid darkened .... I use clear and my reservoir shows clear fluid. Old fluid starts getting gummy and would prevent smooth float operation.

Salim

steven4422

Replacing the brake fluid reservoir cap? will that work on a 2008 lexus rx350. same issue: brake light on constant, chime. Brakes are fine.

salimshah

Have a helper see the instrument cluster as you slide the float up and down.

Salim

maxSteel

I keep one of those medicine syringes (the kind for squirting medicine in a kids mouth) in my toolbox just for removing excess brake fluid.

salimshah

I use the flavor injectors. Just added another one this Thanksgiving.

Salim

torii007

I had the same problem with our 2000 RX300. The solution was to replace the brake reservoir cap assembly (all one part). I had to order one from the Lexus parts department. I simply unplugged the old cap, removed it, and then installed the new one. It was a very easy process.

joebtflspk

Has happened to me during very cold spells. Popped hood, thumped rim of brake reservoir top a couple of times with my finger, problem disappeared. Apparently loosens sensor float to its proper level. Cheap solutions are the best!!

carguy07

That would make me question if the fluid is contaminated with water and needs changed.

gregmacd

I replaced the brake fluid reservoir cap (part # is 84460-30040) on my 1999 RX300, which I found on ebay for $80 and the problem went away thanks to all the previous posters who said to do the same thing!

5 years ago, the brake light came on, and it went away after I added some more brake fluid, but that didn't work this time. So, try adding brake fluid first, before you replace the part.

trhs75

Excellent tip from Greg. Hopefully, it will just be a matter of making sure there's enough fluid. That's a lot cheaper than a new cap, too!

jnotebaert

Hey LA4Mead,
Do you have the site and part # to where you bought the brake fluid cap for your RX 300? I have a 99 and that brake light is ding ding dinging me crazy!!! I googled "brake fluid cap" and price ranges came up from $30-$90 bucks and I want to make sure I don't buy junk or pay too much. thanks- Jack, Phoenix AZ

trhs75

I think it's 84460-30040. I've bought a couple, and they were each just under $100.