I have a 1992 Chrysler Town & Country (I know, not technically a Caravan, but close enough!). It hasn't been driven for about a year because the rear axle failed. While preparing it to get fixed, we tested everything out on it. We got the rear axle replaced.

Both before and after having it replaced, the brake warning lights on the dash will come on momentarily when the brakes are pressed. That is, I step on the pedal, the lights blink on for a second or so, and then turn back off. Braking seems normal, and the brake fluid was completely replaced when the axle was, because he also redid the rear brakes. The fluid level is fine, with no apparent leakage.

Both the Parking Brake and ABS lights will come on when this happens.
The ABS relay was replaced as of maybe a year and a half ago.

Any suggestions on what to check?