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Bad electrical problem with my SD cummins swap

804 views 1 reply 2 participants last post by  Whitetrash303 
#1 ·
Hey guys, like 98% done with my cummins swap but having some big problems all of a sudden.

After trying to figure out my 6.0l starter getting stuck in the flyhweel from not being shimmed, the electronics have gone crazy.

I cant find any fuses blown, but havent checked relays.

I have a new starting solenoid and battery.

Heres the issues.


When we connect the battery, my aftermarket oil pressue gauge goes up and past every number, so we assume theres stray voltage hitting a ground and causing the false reading.

This is with the truck off, nothing on, no key in.

When we turn the key to the on position, only the ABS light turns on but dim.

Weve checked and taken every 12v hot wire ive had hooked up (fans, Airdog pump) and its down to the 12v from the battery to the starting solenoid, and then the white wire that goes to the Cab.

Is there a relay thats blown that could cause this, it seems like it has to be a hot wire hooked up to the cab thats shorting, but we cant find it.

The crazy thing, is my pillar of gauges isnt even hooked up to 12v source anymore, and the oil pressure gauge still shoots up, so it must have voltage on the ground.

When we turn the headlights on, they work but the hood light turns off?

Any ideas? I bet im going to have to the pros in for this one.


As soon as we connect the hot battery wire this happens, and theres a hissing/ticking sound under the instument pannel

Anything i can test to show the voltage in the ground? Test a ground off the body to the neg terminal?
 
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#2 ·
Sounds like you probably just have a bad ground causing it to backfeed. Make sure your ground connections are good and CLEAN. I always run the neg batt cable to the block and chassis, then run a 4 gauge cable from the block to the frame.
My buddy had a chevy with a piss poor ground, his oil pressure gauge did the same thing. He figured it out when the throttle cable took the place of his ground wire and welded itself.
 
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