This is a great resource for Lexus Lovers.
Bought SC300 couple months ago. Runs like at Jet but AC not working at all.
Converted R12 to R134A.
Charged with R134A.
AC worked for one day.
Next Day no AC just hot Air.
Tested Connector to AC Compressor, No 12 V DC.
Suspect fuse or Relay.
MG CLT Relay and tested OK with Normally Open Contacts closing
when 12V is placed across the coil.
Did Diag Test: Code 21 (Solar Detection and 23 (Pressure Switch Circuit).
Compressor (Middle) rotates freely when car is off. Not Locked.

1. Are there any other fuses that could be blown?
2. Is it likly that the Compressor is blown?
3. Converted from R12 to R134A. Could that cause the Error Code: 23 Pressure Swith Circuit)? Does R134A cause a decrease in presure from R12?
4. Where can I buy a rebuilt R12 compressor (Original or after market) for 1992 SC300?

Thanks
Ken

 

Did Diag Test on a sunny day: only Code 23 (Pressure Switch Circuit).
Could it be due to a R134a freon leak ?
Whats the best way to trouble shoot the Pressure Switch Circuit?

 

Sounds lie the freon leaked out as 134a particals are smaller than r12 so more prone to leakage.

 

Use a AC guage set and check your pressure readings. If your AC is low on freon, use a vacuum pump and pull a vacuum to check and see if your holding a vacuum. If not, then you have a leak somewhere and you need to find it. Autozone rents free of charge, AC guage sets (134r) and ac vacuum pumps. Lots of info on the net and youtube how to do ac checks/fill. Walmart sells 134r for $8 can. If your compressor is shot most people use junk yards (be good to the environment..recycle them parts!) or reman ones. New ones are very $$$. In Houston the salvage yards sell used compressors $70-100...haggle with them.