2000 Catera - does Cadillac repair them?
 

Just typed a whole long story with a question, and it disappeared when I submitted it. I guess the Forum Gods would prefer a shorter version. Okay - here it is:

2000 Catera with less than 30K miles, driven only by my mother-in-law to church and back. We got it for my son when she quit driving, and fixed the A/C, replaced battery and a couple of tires.

It passed inspection in June. Right after that, the speedometer and odometer stopped working. And ABS and TCS (I think it's TCS) lights came on. Occasionally works, if it's cooler, but only for a couple miles, then goes out again. I just try to stay with traffic, and I don't speed. I have to drive it now (long story), and I really like the car, but am worried about whether it's fixable.

Brake light also came on, but I had that checked, and brakes are fine. Which makes sense, she wasn't driving that fast!
Leveling light stays on if someone is in the back seat.

Guy down the street can't figure out how to fix it. Should I take it to a Caddy shop? Or just a better local guy?

I have to keep driving this car for a few months, and I can live without the speedometer/odometer for now. I use my GPS for a speedometer.

Thanks for your time and consideration!