Changed brake booster, now 4x4 and brake light are on

[pghguy517]

I replaced the power brake booster, check valve, and rubber hoses on my brake booster, now my brakes work as they should. But after 3 miles of driving the 4x4 and yellow brake lights came on. I'm sure it's related to the work I just did, but not sure what. Any suggestions?
It's a 2005 4.4 X5 sport with 155,000 miles, staggered wheels and a left rear tire that's been leaking for a few weeks now and I keep adding air and resetting the tire monitor system. When I changed out the booster I loosened the brake lines from clips and moved the master cylinder away with lines attached and reinstalled, never opened the system so no brake bleeding needed. I did forget to reattach the brake fluid level sensor wire to the cap before I started it and got a low fluid level warning on dash, but that went away as soon as I plugged it back in. Everything works great and the pedal is not mushy at all.
I don't have the triad of lights or the transfer case actuator gear noise, so I'm sure it's not that (had that happen a couple of times and know that noise well).
I also checked my alternator, 15V at idle.
I hope this information is relevant, just thought it couldn't hurt.
Thank you in advance.