TLDR: if you're having ahc issues after globe replacement, pull and replace the AHC relay in the fuse box, then disconnect the pump,l power connector. Turn on the truck. This seemed to reset the system and fixed the issue.
So I just finished overhauling the AHC system - new globes, pump rebuilt, resivoir cleaned, fluids completely drained and refilled. After this was done, I couldn't get the system to engage. The truck was bottomed out on the bump stops and when I would turn the truck on it would read as being in "N". When I would try to change to H or L the light would just blink endlessly. I bled all 5 and got the last of the air out but still had no success.
While troubleshooting, I pulled the relay to check that it was in good shape and then replaced it. I then disconnected the power connector for the pump to see if it was getting voltage. When I turned the truck on (relay back in box but pump power disconnected) it seemed to know that the pump was disconnected and shut the system OFF and there was no voltage to the power connector.
After this I shut the truck off and reconnected to power for the pump. I fired up the truck again and the indicator showed L this time, and the system worked as expected. I ran it through a few cycles just to get out any last bit of air and the system now goes from L to H in about 20 seconds.
Another complicated system fixed but turning it off and turning it back on.
So I just finished overhauling the AHC system - new globes, pump rebuilt, resivoir cleaned, fluids completely drained and refilled. After this was done, I couldn't get the system to engage. The truck was bottomed out on the bump stops and when I would turn the truck on it would read as being in "N". When I would try to change to H or L the light would just blink endlessly. I bled all 5 and got the last of the air out but still had no success.
While troubleshooting, I pulled the relay to check that it was in good shape and then replaced it. I then disconnected the power connector for the pump to see if it was getting voltage. When I turned the truck on (relay back in box but pump power disconnected) it seemed to know that the pump was disconnected and shut the system OFF and there was no voltage to the power connector.
After this I shut the truck off and reconnected to power for the pump. I fired up the truck again and the indicator showed L this time, and the system worked as expected. I ran it through a few cycles just to get out any last bit of air and the system now goes from L to H in about 20 seconds.
Another complicated system fixed but turning it off and turning it back on.
