2003 WR450F - Factory rear brake pressure switch?

I've got a 2003 WR450f that I just converted to Motard trim (complete with cush drive).  It was plated in MI, but when you bring 'em out of state to TX, you have to go through an entire inspection process.


I started to go over it yesterday prior to inspection and I found that the rear brake light wasn't working.

The bulb is dual-filament and OK.  I looked and there is what appears to be a factory brake pressure switch on the rear master cylinder. 

I pulled the factory service manual for the 2003 - it shows a dual filament bulb, 3 wires (brake, run, ground), but on the other side of that 3-wire connector, there are only two wires...  Here is the diagram - rear light is section "10".


I can't find anything on the factory diagram that shows a rear master based brake pressure switch...


Can someone give me the scoop?  2003s have a factory rear switch or it's aftermarket? 

Edited by dcg9381

I believe it's an aftermarket switch, I don't know of any factory installed switches. I have an 04 model I'm about to install the Tusk DS kit on and I bought switches for front and rear brakes.


Good Luck on trouble shooting, hope it's an easy fix so you an get through inspection.




Thanks for the reply.  I'l pull it apart and see if I can figure it out.

Purchased my 2003 wr450 new...and there is no factory brake switch.

The switch is bad.. Anyone recognize this master or pressure switch?



Yeah, that's the " WASH ME NOW" 3000 model.


I've tried them all, and I recommend staying away from every brand accept the Baja Designs brand.


I've never worn one out, only broken  them with rocks.

Looks like any Chinese pressure switch you can get on ebay for as low as $5.  I've never had any problem with them.  

I can't remember which switch I have, but it's not a baja designs and it's been working perfectly for thousands of trail / dual sport / race miles.

I think I have a tusk out back and a quad master with built in switch up front.  So far so good.  I have a spare tusk that used to be up front.  If they both shit the bed I'll probably get a baja designs.

Thanks.. the switch is bad.

It's tied in to the power distribution box  (with the fuses) under the seat.

I read a few things on ThumperTalk indicating that the pressure switches can be problematic.

There is no switch up on the front brake.  I did look at masters from ATVs (450cc) - but decided if I'm going that way, I'd just buy a master from a DRZ400.

For Texas, the only other thing I need to add is a license plate light, which has been ordered.

I recommend replacing with the same baja switch. I had a different switch and the bolt piece was too big to clear the master.


regarding the front, I spent the $$$ and bought a front master from the street wr250, and that way I got the mechanical switch for the front. Downside is lack of variety with choice of levers..




Edited by SurfaceToAir

Baja Designs.....the one and only company to consider when doing this.

Support second to none.

The parts will be there in a year or two when you break something too

Baja Designs.....the one and only company to consider when doing this.

Support second to none.

The parts will be there in a year or two when you break something too

I must have called the Baja Designs in India.

I've never gotten off the phone impressed

I got a switch from Baja Designs.

The switch is made by K&S.  Works fine..  Cost about $25

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