i think it may be the expansion valve. i got the AC refilled today with 134A and it blows cold for a few (very few) minutes and then turns warm. i have an electric fan set to turn on with the compressor.

the shop said the low pressure was acting strange and fluctuating between 20-50 and they thought it was a expansion valve issue.

is there a guide on the replacement of the valve? if not do i have to remove the entire dash or can it be accessed by going behind the glove box?

truck is an 89 with factory air

thanks

 

I have the same issue. Ill try and search it later

 

discharge the system and disconnect the two pipes at the firewall... you should be able to pull the evaporator box out by removing the glove box... it is a separate box from the blower and heater boxes... you shouldn't need to pull the dash out unlike domestics