85 xj700 electrical issue help

just got my 85 xj700 back on the road last week. took it for a spin over to a buddies house and back, no problems. stopped on the way at a food lion after that problems... in the last 7 miles to my house i lost turn signals and the tach, wasn't till i stopped that i realized i lost the neutral light as well.
i found a service manual for the bike online and checked the signal fuse. it was blown, replaced and it blew immediately. so i unplugged all the signals and replace the fuse again, one at a time reconnecting them, didnt blow. decided to test out on a short trip to gas station, i made it to the end of the driveway and no signals again.
did some more research and figured it must be a faulty reed switch cause it seems to happen when the bike goes more than 50ft or so. disconnected the white/green wire and still the fuse blows. doesnt seem to happen when the bike just sits there with the key on. i could try tomorrow with the bike running in neutral and see if it just blows the fuse after a certain amount of time.
anyone have an idea of something else that would cause this issue? im kinda at my wits end and really dont wanna have to take the entire harness out and apart to solve this issue.

 

Loose ground connection? Frayed insulation shorting during vibration?

 

Is that when you applied the brake?

There are more possibilities than just the signals. The tach, brake lights, flashers, flasher relay, horn, neutral light, oil light, and fuel light. So a fault in power applied to any of these circuits where a wire chaffed to ground as Stumplifter suggested could cause the fuse to blow. More likely it is related to the brake or signal, so try each of these with the bike not running and see if the fuse blows. Make sure to actuate both the front and rear brake as the switches are wired in parallel.

 

i did as suggested and went thru the brake lights. the fuse blew when i hit the rear brake lever, but not the front. i tried the front first for about 5sec or so and nothing then the back and it blew within 2 sec. so i took apart the entire rear fender assembly and light. checked all the wires inside the plastic tube, no frays or splits, couldnt find any thing. the ends connecting into the light itself are good and solid. checked the ends on the seat no abnormalities. tried the light again while it was out of the bike worked fine. put it all back together still works fine. if it doesnt rain tomorrow ill take it out and see if it goes when its moving.

 

You may want to disconnect the rear brake light switch temporarily to help isolate the problem. I know it is possible for a defective front brake switch contact to electrically connect to the plunger, and then when the brake is released the fuse will blow as the switch sends 12V to ground. This has happened to several members after replacing the front switch with a new switch.

The same situation may also occur with the rear brake switch, an internal short in the switch that connects one of the contacts to the plunger and then to ground, which would cause the fuse to blow. Just make sure your front brake switch is working properly and illuminating the brake light for safety concerns when testing.

Another test if you get back to the point of the fuse blowing would be to bypass the rear brake switch and use a jumper to short the two wires, which should illuminate the brake light and help isolate the problem.

Since the front and rear brake switches are wired in parallel and tied together at both ends this should rule out wiring issues in the harness.

 

test the switch

try taking the spring off the brake lever and pulling the pin with it now being connected to the lever.
you may have an internal short in the switch that is conducting down the spring to pedal and frame

if you look at the above wiring diagram you will see little chance for shorts that would be isolated from the front switch
if the gray wire is shorted from the pedal switch it would short for the front switch aswell.
if the brown wire is shorted it would blow the fuse with out the switch being activated

you could also try just connecting the 2 harness wires together with clip leads and a small value fuse (for protection) to see if the light comes on and blows the fuse that would isolate the problem to your brake switch if the fuse does not blow

 

so good news i got to ride the bike around a few times and the issue is gone. i went through the tail light wiring, and didnt notice any fray or broken wires. then i checked the foot switch, no problems but did notice that it seemed any little jiggle would set it off. i think what was happening was the foot switch was set to tight and was creating an arc inside of itself. this was due to the garage i had do the inspection wouldn't let it pass without it been like that..... i backed it off and it seems to have fixed the issue. thanks for the help.