355 - How Do You Jump A/C Compressor Clutch? Relay Location | FerrariChat
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355 How Do You Jump A/C Compressor Clutch? Relay Location

Discussion in '348/355' started by C-speed, Mar 6, 2024.

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  1. C-speed

    C-speed Karting

    Jul 13, 2022
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    Crescent Kao
    #1 C-speed, Mar 6, 2024
    Last edited: Mar 6, 2024
    Hello,

    I'm trying to fix the A/C on my 97 F355. The A/C never worked when I bought it but the compressor was covered in oil and gunk so the seals were obviously shot. So, I replaced the compressor from Ricambi, a new OEM receiver/dryer and evaporator valve. I pulled a vacuum and there's no leaks. I'm refilling the system with 134a, however, I can't seem to find where the compressor clutch relay is so I can jump it to activate the clutch.

    I read in another thread that there are 2 relays in the frunk and I located them but I'm not sure if one of them is the clutch relay and if so, which one.

    Can anyone shed some light?

    If not, I'll have to resort to jumping the clutch wire directly on the compressor.

    Thanks.

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  2. Qavion

    Qavion F1 World Champ
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    Ian Riddell
    #2 Qavion, Mar 6, 2024
    The relays are located under the frunk liner on the right hand side of the fresh air intake for the HVAC. There are two there. The aft one is for the AC compressor.

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    Unfortunately, there are no easy ways to activate the compressor (unless you've already got the car in pieces)

    The green and red wire carry the power (not the black and green/white). Check the condition of the fuseholder and the fuse while you're in there. They have a tendency to melt.
     
  3. C-speed

    C-speed Karting

    Jul 13, 2022
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    Crescent Kao
    #3 C-speed, Mar 6, 2024
    Hey Qavion! How are you doing?

    Excellent, thank you!

    What do you mean? If that's the relay, wouldn't bypassing the relay by applying 12v activate the clutch? As I said in the OP, I can crawl under the car and apply 12v directly to the clutch wire on the compressor but I'm too lazy to get under there and remove the undertrays if I don't have to.

    Thanks!
     
  4. Qavion

    Qavion F1 World Champ
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    #4 Qavion, Mar 6, 2024
    The frunk felt liner is a bit of jigsaw puzzle (and very fragile). I simply mean the relays are not easy to get to (unlike the other relays).

    Doing well, thanks (relatively speaking) :D
     
  5. C-speed

    C-speed Karting

    Jul 13, 2022
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    Crescent Kao
    #5 C-speed, Mar 6, 2024
    Gotcha. Ya, I have everything in the frunk torn apart to replace the AC components and attach the gauges. Got tired of baking in the sun in the summers, so hoping to get the AC working for this summer lol

    So, in case anyone else is reading this, I'm going to apply 12v to pin 87 on the aft relay and see if the clutch activates. I'll report back.

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    Glad to hear! I appreciate your help (again) :)
     
  6. C-speed

    C-speed Karting

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    Crescent Kao
    #6 C-speed, Mar 6, 2024
    Confirmed. The aft relay activates the compressor clutch. Thanks!

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  7. Qavion

    Qavion F1 World Champ
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    #7 Qavion, Mar 6, 2024
    Great to hear. I was going to say that if the relay jump didn't work, there might be an issue with the pressure switch on the receiver dryer, but you've already got the compressor running.
     
  8. Qavion

    Qavion F1 World Champ
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    #8 Qavion, Mar 6, 2024
  9. C-speed

    C-speed Karting

    Jul 13, 2022
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    Crescent Kao
    #9 C-speed, Mar 6, 2024
    Correct. Pin 30 is switched 12v though. It’s only powered when the ignition is on.
     
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  10. fatbillybob

    fatbillybob Two Time F1 World Champ
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    #10 fatbillybob, Mar 7, 2024
    You do not need to activate clutch by hot wiring it. Pull vac and open can nothing running. About 1/2 can will go in. The drive rest of can into not running system by put attached can in hot water. When empty close system. Place can 2 and by now you have enough gas pressure to start car and ac and pressure switch will be triggered to make compressor run. That's my trick works 100% on any car.
     
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