Jump to content
Ultimate Subaru Message Board

A/C Education please , Why 4 AC relays?


Recommended Posts

1996 legacy  ej2.2  .  The A/C Compressor is not going on.  all fuses are good.  But it has 4 relays for a/c i swaped them on at a time with the headlight relay and nothing.

 

any tips or info would be great,

 

thanks

Link to comment
Share on other sites

There is technically only 1 AC relay for the compressor. 

The 4 under the hood labeled as AC relays are for the compressor, main fan low speed, main fan high speed, and sub-fan high speed. There is another relay in the dash fuse box for the sub fan low speed. 

 

The combination is used to vary fan speeds based on compressor operation and cooling need depending on engine temperature. 

 

 

Most likely reason for the AC to not work is the charge is too low due to a leak. 

  • Like 1
Link to comment
Share on other sites

Something to do with AC functions needing different inputs at various times, should check your wiring diagram for the AC circuit to work out how its done ... Got a multimeter ?

i will check for power at the compressor.

Link to comment
Share on other sites

There is technically only 1 AC relay for the compressor. 

The 4 under the hood labeled as AC relays are for the compressor, main fan low speed, main fan high speed, and sub-fan high speed. There is another relay in the dash fuse box for the sub fan low speed. 

 

The combination is used to vary fan speeds based on compressor operation and cooling need depending on engine temperature. 

 

 

Most likely reason for the AC to not work is the charge is too low due to a leak. 

do you know what one is for the compressor ? i want to jump it and see if the compressor starts.  thanks

Edited by winginit
Link to comment
Share on other sites

Pretty sure compressor relay is the rear-most. 

Can also bypass the pressure switch on the drier with a paper clip stuck in the wire connector terminals. 

Can also jump 12v straight from the battery to the wire on the compressor. 

 

I don't normally jump relays because the ECU controls those and jumping the wrong pins could damage the ECU. 

Edited by Fairtax4me
Link to comment
Share on other sites

I pushed the shraider valve to see if it had pressure,  there was none.   so i replace all the rubber 0-rings in the system filled it with coolant the compressor kicked on. and i got 43 degrees at the vents.   i put the seat back an enjoyed.  Fixed !!

Link to comment
Share on other sites

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.

Guest
Reply to this topic...

×   Pasted as rich text.   Paste as plain text instead

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.

 Share

×
×
  • Create New...