What did you do to your NBS GMT800 Tahoe/Yukon Today?

[ScottyBoy]

Yeah, that's the crazy part. U are wired the same way minus that relay to change the negative signal and not a single problem. The factory harness wiring may be a bigger gauge, the doiodes help or something. Once the ac relay blows it creates a short and won't let the fans come on from temp. It's really nerve racking because I had to shut off the ac and then the low trigger works fine. Replace the ac relay and back to normal until it melts and shorts..rinse and repeat.

I know car stereos function better when the proper gauge power wire is used. It would be hilarious to find out I just needed a factory harness..

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Maybe if the aftermarket harnesses were made with 10 gauge wire, bigger relays, and diodes on the relays, then maybe they would hold up just fine. The OEM harness has 12gauge wires, however the main power wire that feeds the relays is a really thick wire probably about a 8 or 6 gauge. The ground is two 12ga wires. And the AC trigger does have diodes on the trigger wire.

 

[Rocket Man]

I really dislike split loom. So I rewrapped my Nelson fan harness with braided and made a 4 ga alternator cable. Here are a few before and afters.

View attachment 184857 View attachment 184858 View attachment 184859 View attachment 184860 View attachment 184861 View attachment 184862

Im just asking, didn’t everyone say those heat up and fry the relays or did i read it wrong?

I had a problem burning up relays. I upgraded the harness to 80a relays with the bigger tabs. They handle the load better. I really had to watch watch my temp gauge when running my ac in the summer. I would blow the high ac fan relay and it would stop my fans from cooling from temp unless I turned off the ac. After upgrading to higher amp better quality relays everything is stable and able to handle the load.

The 00-02 trucks are gonna have more issues because of the way the harness is wired and how often the fans cycle on high. Amp load is too high and I run a 270a DC power alternator so mine really got run thru the ringer..

The harness would be adequate if u can get the fans to operate on ac pressure instead of the ac compressor. Both fans on low seem to draw less amperage than 1 fan on high.

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I have an 02 and have experienced all the melting problems; also switched to the 80a relays and relay block with 8 gauge power and ground wire as well as 12 gauge for the relays and I swear I still see evidence of overheating at the 60 amp megafuse holders I used. I think it's when both fans come on high that's the biggest problem. I also run a 265 amp alternator. I'm going to switch to the OEM harness I bought from @ScottyBoy but I won't know how it does until next Summer when both hit on high.

 

[bottomline2000]

I have an 02 and have experienced all the melting problems; also switched to the 80a relays and relay block with 8 gauge power and ground wire as well as 12 gauge for the relays and I swear I still see evidence of overheating at the 60 amp megafuse holders I used. I think it's when both fans come on high that's the biggest problem. I also run a 265 amp alternator. I'm going to switch to the OEM harness I bought from @ScottyBoy but I won't know how it does until next Summer when both hit on high.

Yeah, i saw the same thing. They are pulling more than 60a for sure. I swapped in a Hella relay and it held up through the summer. I think I'm going to switch to a factory harness. I'll be watching for your install unless I beat ya to it. It's already too cool even in TX to really test the harness. I did some data logging tonight and even doing WOT pulls up to triple digits my truck was at 188 degrees with ac off. Fans barely coming on.

Any pics of the factory harness and the diodes?. Are they just on the fuseblock? That's the only real difference I can think of and maybe better relays but they are not rated anywhere near 80a..

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[#1taho]

Haven't been around guys cause I have been working on getting a travel trailer. I finally got a good one

 

[PG01]

Good stuff, i like

 

[95escahoe]

Yeah, i saw the same thing. They are pulling more than 60a for sure. I swapped in a Hella relay and it held up through the summer. I think I'm going to switch to a factory harness. I'll be watching for your install unless I beat ya to it. It's already too cool even in TX to really test the harness. I did some data logging tonight and even doing WOT pulls up to triple digits my truck was at 188 degrees with ac off. Fans barely coming on.

Any pics of the factory harness and the diodes?. Are they just on the fuseblock? That's the only real difference I can think of and maybe better relays but they are not rated anywhere near 80a..

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This is the OEM harness




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[Tonyrodz]

This is the OEM harness




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I think I also need to get one from @ScottyBoy .

 

[dantheman]

i picked up an 01 suburban LS this week for 300 bux. stupid teen set the interior on fire.

im going to yank the 5.3 out and its going to live on in the mustang project i am starting

 

[Tonyrodz]

i picked up an 01 suburban LS this week for 300 bux. stupid teen set the interior on fire.

im going to yank the 5.3 out and its going to live on in the mustang project i am starting

Post some pics of that crispy interior. How'd it happen?

 

[bottomline2000]

This is the OEM harness




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Well it's obvious now what's wrong with the aftermarket harnesses. That gauge wiring is a whole lot bigger for the power wire and from the fans. I'm sure the smaller wire is building up resistance which leads to heat..ugh..where did u get that harness? It looks new.

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