Cummins Wiring Harness Question.

[Bob H.]

Had a question for the cummins guys, picked up my harness this week and noticed a slight difference on a secondary plug. The shop manual shows this secondary plug as a preheat switch. Do I need this preheater with block heaters? Is that what this secondary plug is for? Thanks in advance.BH

[scenarioL113]

I think it may possibly be for the fuel water separator. I have a cummins PDF file for my 4BT and it shows a very similar if not identical harness plug like yours.


http://www.tadiesels.com/assets/docs/4B ... lation.pdf



2nd page top right

[JP Dalik]

The pink and black and pink were spares in CHIMERA's harness asl, not sure what the engine side orange and red were for- don't remember using them either. We used the pinks for Trans pressure and Trolling valve on off light wire. Used a common engine ground for the negative on each. Both pinks were unused in our 330hp Cummins harness on each end.

If the block heater is going to be on all the time I would do away with the Cummins installed preheaters and their relays now. Should boats ever need to meet emmission standards and your engines are not at 80-110 degrees you will be out of compliance with the pre heaters disconnected at start up (too much blue smoke).............. yup didn't think you cared either.

Ours work great with the thermostats installed, engines stay warm and the electric meter doesn't need a zerk fitting.

So what's the splash date?????

[Bob H.]

JP, Thanks for the feedback, I ran both the trolling valve and transmission switch wire prior to getting the harness, pinks will be spare for me, the wires do have numbers on them but my shop manual has no info on them. The panels have matching main plugs with no secondary plugs. A little smoke wont hurt anyone...splash date...hoping summer 2011..just tying up all the loose items under the deck and running all wires to helm area, my main deck goes from transom to helm area in one piece, hell of alot easier to run all those wires and cables now..Deck will be going on this month...BH