1. Low on freon. 2. Electrical problems. 3. Vacuum problems. 4. Control head problems.
1990 was before GM switched to using Dex-Cool extended life coolant, so any of the traditional green ethylene glycol or universal coolant/antifreezes would work perfectly. Any brand will suit the car well.
Your need to add more r134a Freon. When the levels are not sufficient to cool both sides the car default sends all the cold air to the passenger side and not the driver's side.
Cool Stuff - 1990 was released on: USA: 10 October 1990 (limited)
Cool Paradise was created in 1990.
Cool Touch was created in 1990.
Had this problem for the last 3 weeks and finally found that I had a bad ground from the battery to engine. Replace that wire.
water temp sensor wire grounding out could cause this problem.
Cool Blue - 1990 V is rated/received certificates of: Australia:M USA:R
The cast of Cool Stuff - 1990 includes: Art Mann as Himself - Host
Cool FM was created on 1990-02-07.
Cool Dry Place was created in 1990.
Jesus Was Way Cool was created in 1990.