1994 dodge caravan check engine light comes on after engine warms up. Codes retrieved with check engine light, 12, 32 & 55

These are all the definitions for your codes.
It's hard to give an exact cause for these codes because of there are a number of different items that could cause these.
The first one could be caused by Incorrect camshaft timing,
VCT solenoid valve stuck open or continuous oil flow to piston chamber,
Camshaft advance mechanism binding, or faulty VCT unit,
The others are most likely bad sensors.
I wish I could be more help but it's difficult to trouble shoot this kind of problem without having the vehicle here in front of me.
Good luck

P0012 "A" Camshaft Position - Timing Over-Retarded (Bank 1)

P0032 HO2S Heater Control Circuit High (Bank 1 Sensor 1)
P0055 HO2S Heater Resistance (Bank 1, Sensor 3)