24v electrical nightmare

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

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

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

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

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

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.

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?

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???

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.

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

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Originally Posted by 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

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Is it possible for a stater motor to do the same?

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ill put some better pics up once i put batteries back in and wired up those picks are from a few weeks ago. and im in forrestfield wa. she got a professional tummy tuck, ill put compliance plate picture up to if people would like to see it?

Ok so when you disconnect the positive from the first (LHS looking from the front) battery, you still have the issues. I am assuming you don't have any Aux (third) battery connected up anywhere? Kinda got me stumped as well but going to throw some ideas out there..

The way they are wired up (guessing its the same as my Safari) is :

You draw power from the LHS Positive Battery
A long cable runs from the LHS negative across the front of the car (behind grill from memory) to the Positive of the RHS battery
The RHS Battery negative is then earthed to body etc

How much voltage do you have? Is it leaking 12v or 24v or??..From memory Oil pressure and water temp gauges are 12v (run from a little invertor in the back quarter panel) so may help point in the right direction.

By the look of it though you have something connected to the second battery (RHS) so using it for a 12v Source?

This may explain why you see two different voltages on the batteries. Although I would expect to see the RHS battery lower. If you keep drawing 12v off one battery you will find your battery life is effected and unfortunately with a 24v truck once one goes its a good idea to replace both as the old one will bring the new one down to its level. You can buy battery equalisers, but even they are not perfect.

My first check would be to see if there is any broken insulation on the cable that joins the two batteries (from LHS Neg to RHS Pos) that was shorting out. Even disconnecting the positive from the LHS battery would still leave 12v coming from the RHS battery. So what voltage is leaking? What happens when you pull both the LHS pos and RHS Neg off? Does the problem stay/go away? The fact that when you pull the pos from the first battery and still have stray current got me thinking along these lines. But then again you say you have checked and replaced all of the battery cables so kinda rules this one out..

Pull ANY after market wiring off the batteries leaving only the basic (standard) wiring to run the car.
If the problem goes away, add the extra wiring back one by one and see which one causes the problem.

As 3Dogs said..do things one by one..Its just going to be a matter of taking your time and taking things out of the equation.

"Pull ANY after market wiring off the batteries leaving only the basic (standard) wiring to run the car.
If the problem goes away, add the extra wiring back one by one and see which one causes the problem."
Gotta agree with that.
Also measure voltage on batteries with everything disconnected.

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Originally Posted by 4bye4

"Pull ANY after market wiring off the batteries leaving only the basic (standard) wiring to run the car.
If the problem goes away, add the extra wiring back one by one and see which one causes the problem."
Gotta agree with that.
Also measure voltage on batteries with everything disconnected.

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sounds very logical to me doing it that way

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Originally Posted by threedogs

sounds very logical to me doing it that way

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I got that bit from doka404. Just making sure credit goes to the right person. Or the blame if it does't work. LOL

Quote:

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Originally Posted by 4bye4

I got that bit from doka404. Just making sure credit goes to the right person. Or the blame if it does't work. LOL

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I am happy to share the blame lol

Extremely logical... I told OP to do that back in #5

The only way the chassis can actually be "live" WRT to supply -ve is a high resistance path to Chassis from the Supply.

That could/will be why his 12 Volt instrumentation is playing up, it isn't getting 12 volts WRT to chassis anymore.

On a 24 Volt system the chassis will appear live from the RH battery -ve (it will be 12 volts WRT earth obviously).
But if the OP is connecting a test lamp to LH side -ve and putting the probe on the engine or chassis and the lamp is illuminating then his "earth" isn't an earth IE the earth cable is high resistance.
It could be the engine to chassis earth.

His mention of the globe being brighter at different points screams earthing issue but as we have all mentioned, the only way to go is start at a logical point and go one step at a time.

Best check will be to put the test lamp on the chassis/engine end of the earth cable and go back to battery -ve.
Light on = battery cable faulty
Light off = battery cable OK
If light is off then go to Engine and Chassis and wherever the lamp glows is the broken earth strapping

looks clean enough the patrol that is and looks well looked after {loved]
like all Patrols should be, seems strange its just happened,,,,,,,, as we all know
something had to occur for it to happen, IMO we'll have to wait till he starts ripping wires off
and just seeing whats what.
Mudski for eg re-did a few earths and created more problems, and sounds similar to me
but on a smaller scale

hey guys sorry for not answering back, trust me i have already done that, that was one of the first thing i done was eliminate any after market wiring. and doka404 no there is no 3rd battery and sitting in cab the lhs battery is the 2nd battery in the loop. it goes to earth. i have replaced all positive and earth cable aswell as check resistance for each circuit no signs of shorts yet. im about to install the batteries and see if it was the cable if it hasnt fixed it ill share a video of it. cheers guys

and the cluster is all 24v there is no 12v in it at all. and all the globes in the cluster are 24v. i pulled apart the oil pressure and coolant temp and there is signs of burnt damage to the board but it was still doing it with everything disconnected from cluster aswel so it cant be that but id say it has caused those to instruments to fry out. now im gona have to find a new 24v cluster because i doubt i will be able to find those two parts.

Hi there. Any updates on this topic what was the fault? I hope safari didn't die. I am new owner of Safari and I am experiencing after 2 years of ownership same problem. I get from negative battery lead and from chassis earth 12.5Volts leaks from somwhere.
My problem start when I decided to put led bar on it. I installed everything and it worked ok and suddenly after 3minutes I got on dash warning light on red battery and yellow fuel filter. Now the warning lights are dimming I started to investigate what could happen. I pull off all LED bar harness away. Only what worry me is that i poked firewal with harness in order to install switch. Could I possible damaged wire inside the firewall? and now is shorting in there? When I remove Alternator fuse in engine bay the voltage leak disappear but not fully. There is still on negative to negative 0.7volts leaking. Could be damaged alternator diod on it or something giving these symptons? Interesting is when I switch headlight on it jump to 12.5volts without alternator fuse. Battery is healthy shows 12.7V. Please someone help me to diagnose this problem I know this is strong community and someone is here with similar problem.

Check both batteries and check the connection between them. Sounds like the crossover could be grounding.

Edit: maybe not grounding as you'd have a fire. But there's an issue there. I don't see how you could have 12.5v at ground on a properly earthed system unless one of the batteries isn't connected properly.

Hi Safari 24V owners I have to share what happened with a car at the End. It turned out that negative on battery and negative on earth giving 12.5volts because it is link in series battery found that on internet on wiring diagram on mg previous 24V model. Warning lights were on because 2 alternator diods were off, but alternator was still charging so I couldn't figure out on my own what was going on so I ended up in Autospark shop with bill $330 2 hours labour to find out what is wrong. They found melted earth cable from alternator going behind washer bottle.... and told me that I got 2 bad diods of 6. Then I bought alternator genex branded and Hitachi who knows what it is (china probably) for $230 of ebay which is cheap i think considering there is vacuum pump on it got it changed by myself and warning went off to my luck and is everything working as it should. Now the root cause of my problem started when I decided to install my led bar. I installed all correctly only I could choose better way how to get cable for switch in the cabin. Then I put negative terminal back on battery and for some reason I didn't tight up negative terminal strong enough or something distracted me. Then next morning my battery were low because of all testing for led bar and not properly attached negative terminal caused alternator pushing to much amp trying to charge battery and that would explain burned cable from alternator and overheating diods in it.(My theory). Anyway alternator was more then 7years old and I`ve got expensive lesson, but I learned a lot from this using multi meter and about alternators and 24v systems. I hope this help someone as well one day.

Glad you figured it out.