Just had "Service Ride Control" pop up on the display... I did a brief search and found the fuses to check and verified they are all good. The next step was to jumper pin 30 to pin 87 on the ALC relay harness, and sure enough the compressor fired up. So I went and picked up a new ALC relay, but it didn't do the trick?! So, I tested the original relay with a spare battery I had in the garage, and sure enough the relay kicks just fine... So, back to the harness connector: I have =12v on pin 30 with the Key ON, and I also have 12v on pin 86 with the Key ON, which tells me the system is asking for the compressor to fire up. What I'm lacking at the harness, however, is GROUND on pin 85... So, where is the ground lug for the ALC relay???? I'm guessing it's just corroded or something and needs a good cleaning. Thanks for any help!!!
2006 Denali Service Ride Control
- Thread starter tobyw
- Start date
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SLCHOE
ASE Master Certified + (L1)
It grounds from pin 86 of the ALC Relay to the ESC Module. Pin 85 is not ground as you think it is. Pin 85 is power to the low-amp circuit of the relay. The ESC grounds pin 86 thus energizing the coil in the relay.
Check that wire for continuity from the ESC module connector back to the relay.
Check that wire for continuity from the ESC module connector back to the relay.
