XJ750 Seca - Tail light warning

So I was riding my 1982 XJ750RJ Seca tonight, on my way home and was going to stop by harbor freight. I was running low on gas, and was getting the warning light coming on and off (1/4 means get on reserve - and twisting on the throttle doesn't help :twisted: ).

At a stop light, I see the warning light come on again. I'm about to just ignore it, but I notice this time it doesn't say FUEL, it says TAIL.

I bounce around on the seat, check the brake light, but the warning goes out, and the traffic light turns green. When I get to the parking lot, I check the rear light and everything is fine. What circuit does that warning light pertain to? And what else besides the rear running light and brake light should I be checking for a loose connection or something else wrong? How does that display determine there is a problem? Could there be a short in the display?

 

I know Dez was getting a tail warning when only one of his 2 tail bulbs were blown. Maybe it's just one that's gone in your case?

 

i have a 81 xj750r and my tail lights wouldnt work but the bulbs were good ,they wasnt getting power so i ran a wire from the head light fuse to the lighting wiring harness and they started working along with my gauge lights.but since ive done that my tail light warning light has been flashing. i think we both have a loose connection somewhere, or a corroded harness, or its not wired properly.hopefully we get some help on this issue!!!!

 

Jaymckn... there is a glass fuse in th headlight bucket for th tail light, maybe its blown or dirty. On mine its th only one in there. ...ManBot..can't help, sorry.

 

It went away...and came back...then went away again. Both tail lights work, and come on brighter with the brakes. I guess I just won't worry about it til the warning comes on again and doesn't go away

 

Ok well now I have to worry about this. I noticed that my blinkers go out and stop blinking when I step on the brakes. The come back on and blink as soon as I let off the brakes. I'm guessing that means a short somewhere in the power side of the brake light circuit, since all the taillights in the back share the same ground.

I didn't notice anything wrong and after a little troubleshooting the problem magically went away. But of course not for long. I noticed in the wiring diagrams that it's hard to follow how the brake switch wires go into the atari, and come back out to supply power. Anyone got any good ideas to test this?

 

Ok...apparently, my charging system was at fault. As the battery died, it could only run the blinkers and tail light but not both. The 3 white wire connector from the alternator was melted, so the wires were shorting out on each other. I spliced in some weather proof spade connnectors, and it all seems to be working now.

Except that my headlight doesn't work. I will check the charging system output again, but I noticed (with the bike running) that there are 12 volts coming out of one of the two wires and ground (I think it was the main headlight wire) but that the high beam switch doesn't put voltage to the other wire. How should I start troubleshooting the headlight, and could it be connected to my 3 white wire alternator connector melting? Why would that melt?

The sad thing is, I just put this bike (1982 XJ750 Seca) on the road this spring. I've put 3k miles on it (which I'm very proud of) and the last 1500 have been rather trouble free, but I need it to work for a 400 mile trip to DC (moving), and it just seems to be getting a whole host of "new" problems.

 

Make sure you check your alternator brushes too!

 

I checked them at the beginning of the season, they were well above the wear mark.

 

Finally figured out my tail light problem. I kept getting the warning after revving the hell out of the bike, then after another good rev, the warning would go out. Finally caught it on, when I got home. Looks like it was just the filament in the left bulb. Going to replace that tomorrow. 6 months later, easy solution!