warning light comes on when I hit a low speed bump

Me again.. The red warning light comes on with my XJ750SECA when ever I hit a low speed bump. One answer is,, I avoid low speed bumps. Not practical.
My battery light is always on because I don't have the battery insert and my oil pressure light has always been on. Had pressure checked and its fine. I was told the sending unit tends to stick so I'm not worried. I'll get to these in off season.
When I hit a pothole or man cover, the brake warning light comes on for 1/2 second then disappears, but warning light starts to flash. I can cancel it easily until the next hit. Any thoughts ?

 

One of two things.

One, you've got a poor connection somewhere, and the brake light it actually cutting out. Try shaking the wire, all along the way, and see if it triggers the warning or if the tail light flickers. May be a failing tail light bulb too.

Two: the current sensing switch is failing. Not sure really how to bypass this (it's an issue for me as I've LED tail lights, so my tail indicator is on all the time anyways), but there's a thread about this with regards to the headlight current sensor somewhere.

 

There is no oil pressure sensor. It is an oil level float. Run the proper dose of Seafoam in the sump until your next oil change to free up any accumulated sludge that's making the float stick. If the light still stays on thn you should check that the float is hooked up (it's on the bottom of the oil pan, and he wiring harness runs along the lower left frame tube).

The BRAKE warning light is also tripped by a float. Your brake fluid level is too low. Check for leaks in the system. Top it off if you find no leaks. Rebuild the brake system if you have not already done so.

If it were a problem with the brake lights you would see a TAIL warning.

 

Thanks k-moe!

Well, that's embarrassing. Yeah. Dunno why I read that as the tail light indicator, and didn't even think of the brake fluid level sensor. *Sighs*

 

Thanks guys. "proper" dose of sea foam ? I'm running semi-syn now. How much is a proper dose , or is this listed on the can ?
I've replaced brake fluid and pads last year. I'll check the level but surprised if it's low. On that note, I see custom kits for under $50 (not including new brake lines)converting to a brake cylinder on the handle instead of the crappy cable/reservoir system they have now. I have original lines and plan to upgrade sooner than later.

 

Instructions are on the can.

The master cylinder is odd, but it's no more or less crappy than the other master cylinders of the era (though you do lose fedback because of the cable). What is crappy are the 30 year-old brake lines and cylinder seals. An upgrade will tansform how the bike brakes.