1995 m1078 not getting any power after unhooking batteries and welding on frame?

I have replaced all fuses and relays along with the batteries (2 napa commercial 7236), and i have also cleaned all of the grounds. i have around 13 volts at each battery and around 13 volts on the 24v side of the reverse polarity box and nothing at the 12v side in the fuse panel? Since i hooked the batteries back up there has also not been not power to the hydraulic control box, dash, master switch, light switch ETC... Is the reverse polarity box the culprit and if so does anyone have one that is in working order for sale or should i look elsewhere? Any help would be greatly appreciated as i do not know where to go from here. i also checked the wires behind the fuse panel and cleaned everything. thanks in advance..

The polarity box has 4 connections. 12 and 24 volt in and 12 and 24 volt out. Measure the v-in and then v-out. Should only be around 1/3 of a volt drop across each

Where did you have your welders ground clamp attached to the truck?

Are you sure about what terminals on the polarity box you are measuring? 12V at the 24V terminal sounds like the first issue you need to overcome...

What polarity box is on a 1995 truck?

did you swap to the new battery configuration after the welding or is it the same configuration that you took out? I'm guessing new batteries and new configuration.... and it is hooked up wrong so you got no 24v

ground clamp was attached to the back by the pintle hitch

under the spare

It was already configured with the two napa batteries and i hooked the up the same way as they were, but thats not to say that they are not wrong. I am by no means electrically inclined and if anyone could help out with how the two batteries should be wire and how the polarity box should be wired would be a great help

12v comes of the battery closest to the front of the truck negative terminal. Yes positive is drawn from that negative terminal.

sounds like you could test to see if reverse polarity box got damaged via bypassing it... 12to12, 24to24. if that works then you know your problem. Is there a circuit breaker on the unit maybe? Obviously if you bypass it you **** well better make sure things are wired properly though or you create whole new set of big problems

Any update ?

Things are wired correctly, but still not getting anything as far as the 12 volts up to he polarity box and only getting 13 volts on the 24 volt side?

Is there a circuit breaker anywhere on the truck, i have not been able to find one

Where is your polarity box located?

If you are at the batts and you have 12v between the two and at the lead going to the 12v side of the polarity box thats 2 feet away follow it to the box and see whats going on.

do you have 24 volts at the nato connector? if not the batteries are wired wrong.

Longlock10 said:

ground clamp was attached to the back by the pintle hitch

Click to expand...

And where were you welding?