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

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j91z28d1

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apm? air pressure? if so as far as I know the air pressure commands are for testing only


I looked again. it seems to be a hybrid thing. under powertrain, accessory power module, special functions. I get apm setpoint control.

while in there I did see the cooling fan test for relay 1, 2 and 3. these trucks use a resistor pack on each fan to make 3 speeds. 1 sounded like low speed and both fans came on. 2 sounded litter faster and both came on. 3 was crazy loud but only the passenger side came on. guess I gotta dive into that and see with summer coming. I remember looking at the wiring diagram once and getting a slight headache lol. guess I'm diving back in.

I'm not even sure it should run both for just relay 3 turned on. I turned the ac on max with the windows down but it's not hot enough, high 80s at best. could only get high side pressure up to 198 and relay 2 commanded on. 3 never was.
 

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Doubeleive

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I looked again. it seems to be a hybrid thing. under powertrain, accessory power module, special functions. I get apm setpoint control.

while in there I did see the cooling fan test for relay 1, 2 and 3. these trucks use a resistor pack on each fan to make 3 speeds. 1 sounded like low speed and both fans came on. 2 sounded litter faster and both came on. 3 was crazy loud but only the passenger side came on. guess I gotta dive into that and see with summer coming. I remember looking at the wiring diagram once and getting a slight headache lol. guess I'm diving back in.

I'm not even sure it should run both for just relay 3 turned on. I turned the ac on max with the windows down but it's not hot enough, high 80s at best. could only get high side pressure up to 198 and relay 2 commanded on. 3 never was.
might be a hybrid thing, on the gas trucks both fans come on no matter the speed.
that's how I found out one of my fan motors was bad, right side was not spinning reached down to see if it was froze up bumped the wire harness and it kicked on, discovered the motor was going bad and had partially fried both sides of the connector
 
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j91z28d1

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might be a hybrid thing, on the gas trucks both fans come on no matter the speed.
that's how I found out one of my fan motors was bad, right side was not spinning reached down to see if it was froze up bumped the wire harness and it kicked on, discovered the motor was going bad and had partially fried both sides of the connector


yeah its a hybrid thing. I think I finally wrapped my head around it after having to draw on the diagram lol. 3 trigger wires from the ecm controller 5 relays to give them 3 speeds. I think pro damand labeled the one low but it's also the high speed too. so all 3 input have to be on you get hi to both fans and tech 2 was just triggering 1 for #3. there is an option 1,2 and 3 but when I did that it sounded more like med. the one on hi sounded much louder but I didn't have the truck on, just the key forward. so running both fans on hi off the 12v was probably dragging the voltage down.

I'll have to wait till it's hotter or maybe block some the air to the condenser, get the hi side up enough for request 3 to enable and see what the fans do.
 

Rocket Man

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I love this Griot’s Speed Shine this time of year. The Silvy only gets dusty and if I wash it I have to towel dry it or else it gets water spots. This thing looked terrible and I cleaned it in about 10 minutes with the Griot’s and a microfiber towel. Ready for tomorrow’s grocery run. :happy107: 53DD23BD-D21C-4678-96DE-EB6C3BD90A07.jpeg4E09FDC3-29B5-4569-B835-CC55F1A3B28D.jpeg
 

iamdub

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I love this Griot’s Speed Shine this time of year. The Silvy only gets dusty and if I wash it I have to towel dry it or else it gets water spots. This thing looked terrible and I cleaned it in about 10 minutes with the Griot’s and a microfiber towel. Ready for tomorrow’s grocery run. :happy107: View attachment 400557


I have the same tire inflator. Branded "TiGaAT".
 

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