HELP...BC 763 G ....pops relay when i turn ignition sw on...

[1awert1]

I have a BC 763 G 2400 hrs. on it. has always ran excelent, until today. big storm here and after i got the driveway all cleaned out, i shut it off , about half hr. later i went to start it, lights came on as normal, went to turn it over and everything died, no power anywhere at all, found relay marked "ST. SWITCH " was bad, i replaced it, turned key and all lite up, perfect......until i went to turn it over, then the relay blew again... any idea's ????? there is a starter relay and a switch relay and the sw relay is the guy going.......

 

[1awert1]

some info....i do not have to turn switch to the START position, only to the "ON" position, then after about 1 or 2 seconds, the relay pops...and everything is dead.....

 

[OldMachinist]

some info....i do not have to turn switch to the START position, only to the "ON" position, then after about 1 or 2 seconds, the relay pops...and everything is dead.....

Pull fuse 10, 11 and 12 and see if it still does it. Those are the circuits that come off the switched power relay. If it doesn't pop install each fuse one at a time and try it until you find which circuit is shorted. If it does it with the fuses out then the problem is in the wiring or the relay socket.

 

[1awert1]

Pull fuse 10, 11 and 12 and see if it still does it. Those are the circuits that come off the switched power relay. If it doesn't pop install each fuse one at a time and try it until you find which circuit is shorted. If it does it with the fuses out then the problem is in the wiring or the relay socket.

thanks, i will have to get more relays, then i will give it a go......

 

[OldMachinist]

thanks, i will have to get more relays, then i will give it a go......

I was thinking about this today and the fuses should have protected the relay from too much current draw. Have there been any added accessories or attachments wired in to the machine?

 

[1awert1]

I was thinking about this today and the fuses should have protected the relay from too much current draw. Have there been any added accessories or attachments wired in to the machine?

fuses 10,11,12 are good, haven't pulled yet, to cold out....but nothing new has been added, ran great, i shut it off , went inside to warm up, came out turned it on, it started great, lowered the saftey bar hit the green "RUN" button and instantly stopped, completely dead, found START SW. relay to be bad, replaced it, turned key to ON, all lights come on for 1 second, then pop, relay blown.....

 

[OldMachinist]

fuses 10,11,12 are good, haven't pulled yet, to cold out....but nothing new has been added, ran great, i shut it off , went inside to warm up, came out turned it on, it started great, lowered the saftey bar hit the green "RUN" button and instantly stopped, completely dead, found START SW. relay to be bad, replaced it, turned key to ON, all lights come on for 1 second, then pop, relay blown.....

Which relay is it? "switch power" or "starter"

 

[1awert1]

Which relay is it? "switch power" or "starter"

switch power........9,10,11 are good...

 

[OldMachinist]

switch power........9,10,11 are good...

I'd pull the fuse/relay box out and check the back side for something shorting out the wire/terminal that comes off the relay terminal #87.

 

[1awert1]

I'd pull the fuse/relay box out and check the back side for something shorting out the wire/terminal that comes off the relay terminal #87.

when i turn the key to RUN should i see 12V between leg 85 and 87 on the relay.? ? ?

 

[1awert1]

when i turn the key to RUN should i see 12V between leg 85 and 87 on the relay.? ? ?

i was behind the fuse/relay box and didn't see anything unusual.........this is getting bleaker every hour as i need the BC,,,,it does snow up here....a lot lately.....

 

[OldMachinist]

i was behind the fuse/relay box and didn't see anything unusual.........this is getting bleaker every hour as i need the BC,,,,it does snow up here....a lot lately.....

Yes, you should see 12 volts between 85(12v neg./ground) and 87 on the relay with the key in run position.
12+ from the 100 amp main fuse comes in on terminal 30 and when you turn the key to run the relay is energized sending 12+ to terminal 87.
Have you tried it without the fuses installed yet?

 

[1awert1]

Yes, you should see 12 volts between 85(12v neg./ground) and 87 on the relay with the key in run position.
12+ from the 100 amp main fuse comes in on terminal 30 and when you turn the key to run the relay is energized sending 12+ to terminal 87.
Have you tried it without the fuses installed yet?

I was out there this morning, noticed my right (as sitting in the seat) front head light was falling out of it's inclosure, so i removed the rubber seal and just let it hang there until i got the problem solved....and wouldn't ya know it,,,,,i got into the cab, turned the switch and everything lit up, without blowing a fuse/relay......talk about lucky....something loose or shorting up there behind the ignition switch. should be ez going now (I hope) ....going into town to find another relay so i can put it back together.....I will keep ya all posted......