Hot batteries

[carc383]

I have a m998 today used it ran fine but when I shut off everything is dead. Nothing works I checked batteries and they where very hot I’m thinking maybe alternator overcharged them I noticed gauge in red ? Is there a fuse or were do I start looking to find power again? I changed alternator last year because of not charging. Thanks if anybody can give me advice

 

[porkysplace]

Probably burnt the power control box.
Have you updated the ground harness ?

 

[warcow105]

Throw a meter on the batteries to see if you have juice. If you cooked them then just replace them. If that fixes it and you can start the truck, measure and see what voltage the alternator is putting out.


Mike

 

[papakb]

Be careful when you measure the batteries and charging circuit. A new set of batteries will hold the voltage down to around normal when the alternator is not regulating properly. I had an M151 once that cooked the batteries and when I measured the alternator it was reading 28.9 volts in the vehicle but when I put it on the bench it was actually outputting 90 volts!

Never connect or disconnect the batteries with the vehicle running, it's the best way to kill the alternator and be real careful when removing the connector cover on the alternator, it's easy to short the full output of the batteries to ground if it hits the large output post.

 

[TOBASH]

Be careful when you measure the batteries and charging circuit. A new set of batteries will hold the voltage down to around normal when the alternator is not regulating properly. I had an M151 once that cooked the batteries and when I measured the alternator it was reading 28.9 volts in the vehicle but when I put it on the bench it was actually outputting 90 volts!

Never connect or disconnect the batteries with the vehicle running, it's the best way to kill the alternator and be real careful when removing the connector cover on the alternator, it's easy to short the full output of the batteries to ground if it hits the large output post.

AND DISCONNECT BATTERIES TO ENSURE PCB/EESS NOT DAMAGED!

Sorry for yelling but hey, really important point.