Automotive Electrical Question - F250 Upfitter switch

I have a 2019 F250 Lariat super duty. There are (6) upfitter switches in the top center of the cab that come pre-wired to relays in the engine bay.

a few years ago, probably 3 at this point, i installed rear Air Lift air bags and an onboard compressor/pressure gauge kit just like this one. I was towing a heavy trailer fairly regularly and this kit has performed flawlessly since install. i routed the power for the compressor to upfitter switch #6 relay. so the gauge backlight and compressor cannot run without the upfitter switch being on.

today i got in my truck, noticed the bags were a little low (i like to keep them around 20 psi for daily driving) so i pressed the rocker switch on the air lift cluster and the compressor kicked on, and then cut off. it will no longer turn on.

i think my compressor has kicked the bucket, but, figure ill check it out. inline 15 amp fuse: good. multimeter says i get 9 volts momentarily at the compressor terminal when my wife presses the switch and im under the truck with the multimeter. so shes holding the switch down which should continuously send power to the compressor, but it spikes at 9 volts then drops to zero.

is the switch bad? i pull the wires off the terminal on the back of the switch and manually jump them together while using an alligator clamp to the multimeter so i can see what happens. same momentary spike in voltage, 9 volts, then drops to zero.

so... is my relay bad? the upfitter switch is on, and power to the air lift switch should be constant at a steady voltage right? and manually pressing the air lift switch would close the circuit, sending that power to the compressor. which it does, but only for a brief second.

i can manually inflate and deflate the bags, i plumbed the air lines to a convenient spot so its not going to kill me to not have the compressor, but i want to figure out the issue. the truck is still under Ford warranty (factory extended warranty) so if the relay is bad ill have the local ford dealership take care of it.

 

Had to go through my amazon history, it was actually this kit.

 

How hard is it to switch it to one of the other 5 switches/relays?

 

Probably not hard, I'll try that next I think. I am also going to just hard wire (no switch or relay) from battery to compressor and see what happens there.

 

I would imagine pretty easy. Just transfer the power wire in the fusebox to the compressor from the current switch relay to another one.

 

I. Am. A. Complete. Fxcking. Moron.

I work on Air conditioning and furnaces all day. I have 3 screaming kids running around me while trying to troubleshoot.

AC is not DC. Jesus Christ I'm stupid.

Anyway, when switching the multi meter to DC everything checks out and the fucking compressor is bad.

So dumb. Thanks @A. Barrister, switching relays helped me narrow down the problem (me) and it's solved, other than me sourcing a new one

 

Been there, done that, wrote the book on it. Multiple volumes.