DOSE ANYBODY KNOW WERE TO FIND WIRING DIGRAM FOR A 250 ST-7 OR ANY HELP
ROD

 

Rod,

I don't have a wiring diagram specific for your quad.

When I saw that you had 2 posts to your name I looked at the first of your two posts here:

http://forums.atvconnection.com/chin...to-st-7-a.html.

I missed that somehow .

Is this the same problem? You have 27 amp current draw? You have connectors that can plug into multiple places?

1) What is the history of this quad? Has it ever run in your presence? Is the wiring harness pristine, or does it look like it has been modified?

2) You said you had a 27 amp current draw when the ignition switch is on. How did you measure this? That would actually be a difficult measurement to do since most meters are fused at 10 amps. Note: I'm just gathering info - not trying to put you on the spot. If you don't know how you came up with that answer, or maybe doubt the earlier results now, then just say so and we will take a small step backward and regroup. I need to know how you are measuring current before we start figuring out where the excess current is going.

Even though we don't have an official wiring diagram, most chinese quads have only a few basic wiring schemes. So with some meter measurments and some thought we should be able to figure it out .

 

HI Lynn
It ran when we got it worked for one summer. It sat for the winter got it out to clean carb. Then seen the coil and brake light wires were burent. Replaced the wires and found some conection were crimped so solider them up. took harnnes out and checked out the harnnes. came to hook up the conections up they can be hooked uo differnt was . the fuse would blowe out hooked a ampe gauge in place of the fuse when i unhook the key switch the draw goes away. I took the key switch apart and when i trun the key on it conections the red and black togheter red is power and black is ground.There is a digrame in the back of the book but it for a ST-6 . To check the amps i used a ampe gauge from a John Deere 2 cylinder that gose up to 30 amps. Hope this makes some sence for you if not get back to me

Thank You Verey Much
Rod in MN

 

OK. I understand what you are doing now.

What are the colors of the wires going to your ignition switch? Please give the colors of the wires in the harness, not the short pigtail wires from the harness to the switch. There are both ground and +12 volts on this switch, but the black wire is not necessarilly ground. Black is commonly used for switched 12 volt power wiring on some quads (and green is used for ground). And black is used for ground wiring on other quads. Is it possible your ignition switch has had the wiring altered such that 12 volts really is tied to ground, or is your black wire just ordinary switched 12 volts?

See if you can find a wire from the harness that ties to ground - in other words it has a lug crimped to it and it is bolted to the engine or the frame. What color is it? Black or Green?

The way to isolate where excess current is going is to unplug every connector except the ignition switch. You should be able to turn on the ignition switch without blowing fuses at this point. If not, then that a different direction to follow (which we can do if necessary)...

Let's assume you can turn on the ignition switch *without* blowing the fuse when all the connectors are unplugged. Then you start plugging in the connectors one by one until the fuse blows. Then you look at what the connector plugs into, and that gives a big clue. Once we know what is blowing the fuse the next step will be a little more clear...

Note that this is a divide and conquer operation. We isolate the problem to a narrower set of possibilities. We regroup and narrow it down further with more tests based on the previous results.

See what you find with the above tests and report back. We can continue from there...

 

HI Lynn Got some time to check out the wireing the wires going to key switch on the harness is Red Black Green Black w/ White strip. There is a green wire going to the ground post on the battery. It looks like the key switch has not been change or altered. When the harness was hooked up the draw did not show up till the key was truned on unhook key switch it was gone. Then left key switch hooked up then hook up one connector one at a time the draw did not changed when other connector were hook up. I will try and scan a copey of the wiring digram. When we figger it out

Thank You
Rod

 

Rod:

I have a quick question.....

you stated that you removed the harnes to check it. when you say "remove" did your physicaly uninstall the harnes from the bike? as in remove it and set it on the bench and test it.

 

HI ram50

I took the harness out to solider the conection togther it was all the green wires for the ground system. Did not take wires out of the concetor and to check for burened wires just the coil and brake switch wire meteled by he muffled

Rod

 

Those colors follow a common color code:

Red: +12 volts from fuse
Black: +12 volts switched on and off by ignition switch
Black/White Stripe: Kill Switch wiring
Green: Ground

When the ignition switch is on the red and black are shorted together. When the switch is off the Green and Blk/White stripe wires are shorted together.

 

Well that clears up a big mystery . When you said the coil and brake light wires were melted, coupled with the 27 amps of current flowing out of the battery, I assumed the wires were being melted by the 27 amps of current. Try as I might I could not think of any wiring scenario that that could explain this which involve both the brake switch and the ignition coil. It never crossed my mind that the muffler could be the culprit .

So we're back to where the 27 amps of current are flowing. Again, unplugging all the connectors to stop the current, and then plugging them in one by one is the way to go (as described earlier).

What happened to your main fuse? It is supposed to be 10 amps, and not allow 27 amps of current to flow....

 

Rod.

Good job on soldering the wires. Thats the only way to do it. The main reason I asked that question is..... well...... could there have been a connector that was plugged into the wrong spot. I'm not trying to say you did but I have seen stranger things happen. Just trying to cover all the bases