What did you do to your NNBS GMT900 Tahoe/Yukon Today?

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Fless

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iamdub

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My 2004 NBS is a 4 pin (but only has three wires) and no RVC.

I see there are some two-to-four adapters. Wonder if there’s harm trying out an OEM 160 or 220 like you mention?

I read that those adapter harnesses don't really do anything but adapt the physical harness and only connects one of the functions. You can replace the regulator inside with the correct pins, though. Requires very little, but easy modding for fitment and minor soldering.
 

mattbta

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what does it do when you run just the 1 pin with 12v excite, running just the one pin will throw the light on the dash but alternator will be working
View attachment 405299
That’s what Mechman had me do. Knew it was excited because it hummed a bit, but still only low 12v under high load. Super weird because I’m 100% OEM electric wise aside from the electric fan conversion, and obviously the upgraded wires for the Mechman. I’ll start a thread in a bit in the NBS section. Sorry all! :)
 

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I got one of these a few years back when they were about $125 but from eBay. They'll do the low DC current measurement with the small jaw, but it's only a 1/2" hole. Worked great to find a few parasites...


 

j91z28d1

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oh, on a side note. I stumbled onto a box that will take a normal relay turn on trigger and use it to put out a pwm for brushless fans. it's not really adjustable but it will take the low signal and put out like a 30% and then high be 100%. I know the normal trucks only have 2 speeds but mine has 3 and the box does up to 3, so I'd get a low med high. and those points are adjustable with hp. so with this crazy tx heat it got me thinking about finding a setup of newer brushless fans from one with a high tow rating and see if they bolt on. I'd guess if you found the right part number or rpo code they would be cheap oem take offs on eBay.

should cool better for less power drain than my old brushed ones. box isn't cheap thou.
 

Doubeleive

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That’s what Mechman had me do. Knew it was excited because it hummed a bit, but still only low 12v under high load. Super weird because I’m 100% OEM electric wise aside from the electric fan conversion, and obviously the upgraded wires for the Mechman. I’ll start a thread in a bit in the NBS section. Sorry all! :)
are they going to warranty it? or did they say to send it in for repair? I don't think they have much of a warranty period but they will repair them
 

mattbta

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are they going to warranty it? or did they say to send it in for repair? I don't think they have much of a warranty period but they will repair them
Richard said they would warranty it, but I’m not 100% certain it is the alternator since the 19 year old OEM one does the same. Still have to pay shipping and be back on OEM while I wait.
 

j91z28d1

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My 2004 NBS is a 4 pin (but only has three wires) and no RVC.

I see there are some two-to-four adapters. Wonder if there’s harm trying out an OEM 160 or 220 like you mention?


ahh.. yeah, it won't really work. correctly for you.. it would default to 13.7v at the terminal and not reference anything. I don't know. about the check. engine light thou.. the mechman is probably the better bet.

the newer 220am ones, I haven't found anyone that sells the regulator swap from 2pin pwm (I think they are calling these hairpin style because of the rear fins) to the old school ones, only the older style alternators but they do sell a stand alone back that you can adjust the pwm from and set the voltage you want. it's about 80$ or so.. or can be made for 20$ from ebay parts diy.

I didn't realize you had the older style.
 

j91z28d1

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since you gotta send it back, if you did find a cheap used one like iamdub got(and found me) , this would be what would control it.

 

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