24v electrical nightmare

[peekinggq]

hey everyone my 1988 dual cab gq patrol is a 24v joby and all of a sudden the chassis is live? bullbar aircond tubes the donk everything is live. has anyone had this happen before its got me stuffed. even with the positive disconnected off the 1st battery, and whats even more spun out no fuse relay or nothing has fried it self. the only thing that i notice when it all happen was i lost engine oil pressure and lost coolant temp and then my volts went up to 28.1v. checked the batteries and 14.7 out of second and 13.4out of first battery. this is the first time in 7 years ive ever had a drama with the old girl and the 24v circuit. the worst issue im dealing with is no 24v wiring diagram i can go off. everyone i speak to or ask havent or has never seen one??

any suggestions will be appreciated

[Nightjar]

http://www.patrol4x4.com/forum/nissa...-diagram-2014/

[threedogs]

what are you getting off the back of the alternator volt wise, Alterator could be poling
Also is it live when the motor is running or turned off

[peekinggq]

live when car just sitting there not even the keys in the ignition.

[the evil twin]

What do you mean by "live" IE what voltage do you see between where and where.

Is it the same between engine and chassis, engine and battery, chassis and battery

How much power is in the voltage IE is it just a floater or will it light a say 10 watt light globe

I don't quite see how you can have a circuit with the +ve disconnected from the battery other than thru the 12 volt converter (which sounds like it may have failed).

Try disconnecting leads all leads including the Alternator sense at the battery and look for which one reintroduces the issue

Where are you and where did the vehicle originate, 24 volt dual cabs aren't exactly a common critter

[4bye4]

I'm a bit confused mate. What and where are you measuring? Chassis should be earthed (-ve) and to measure you would check between +ve and chassis. If you are seeing +ve on the roo bar etc, what earth are you using?
I think the oil pressure and water temp gauges are both 12v and they have a converter circuit behind the dash somewhere. Probably only a centre tapped ballast resistor. If this had shorted it might allow 24v to chassis - not sure. I'm trying to be helpful but don't know much about the 24v Patrol. My experience is on a 24v Mazda/Ford truck a few years ago.
14.7 volts on your second battery is pretty high if it is not switched on and under charge. That battery could be high resistance internally. If you can get a load tester try each battery seperatly and check the discharge.
Some trucks use a resistor to split the two batteries to get 12v as mentioned above. That can cause one battery to fail more often than the other and also can upset the charge system.

[the evil twin]

Agree with ^^^^
Voltage splitting can cause unusual problems

... and I forgot to ask is there anything electrical you have mod'd, fitted, played with recently?

[threedogs]

only do one test at a time then you will find out what has caused the problem.
Interested in what the problem could be, do you have a winch fitted ??,
and by dual cab you mean a real dual cab or just a high roof 4 door.
Pic would be good ,,, what area are you in???

[mudnut]

Sorry for the hijack, but we need those diagrams on this forum. Some kind member with lots of data please obtain them. I would even put them in my RB30 sticky thread just to have them handy. Cheers.

[peekinggq]

guys i am just as lost as use. i understand electrics pretty well ive always been confidant in faults in the past but this one has me buggered. its live everwhere at bull bar aircond tubes thermostat block firewall front quarter fender, ive pulled the hole harnes out from engine bay and inspected each wire no damage ive replaced every battery lead and crimp and cleaned all earths, ill just double check the volts ive just been using a 12v to 24v test light some spots are brighter than the others so ill head back out there and lets use no exactly what it is. its got me so confused becuase something should be on fire by now haha. im just charging the go pro and im gona record it and put up so everyone can see im not fried haha. beer times first. ill keep everyone up to date and get back to your answers asap cheers