How to jumper A/C Pressure switch?

JERRYCL

MEMBER
2002 HYUNDAI ELANTRA
4 CYL
2WD
AUTOMATIC
124,000 MILES

The A/C compressor clutch will not engage because of low R134a pressure. Went to jumper pressure switch to start charge but found 4 contacts rather than two. Which ones to jumper and not mess up? Diagram female socket please.

Thursday, March 31st, 2011 AT 8:54 PM

7 Replies

SATURNTECH9

MECHANIC
30,870 POSTS

If you start putting refrigerant into the system it will turn on by itself you don't need to jump anything.

Triple Pressure Switch On A/C line, near right front strut tower.

Here is a guide and some diagrams (below) of the ac pressure switch.

https://www.2carpros.com/articles/air-conditioner-how-to-add-freon

and

https://www.2carpros.com/articles/car-air-conditioner-not-working-or-is-weak

Please let us know what happens.

Cheers,

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Thursday, March 31st, 2011 AT 9:32 PM

JERRYCL

MEMBER
4 POSTS

Compressor clutch won't engage because the switch inactivates the clutch circuit. Will be charging on the low pressure side of the system, but nothing will happen until I cant get the compressor running. You can still add refrigerant into the low side and it will bring system pressures up so the clutch will engage.

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Thursday, March 31st, 2011 AT 10:46 PM

SATURNTECH9

MECHANIC
30,870 POSTS

When the pressure increases from charging the compressor will kick on. Just open the gauge and let the system take in refrigerant and the system will kick on. If not jump the yellow with the yellow and black this should turn the compressor on here is the ac wiring diagrams below so you can see how the system works.

I would check for a leak as well.

https://www.2carpros.com/articles/air-conditioner-leak-detection

Check out the diagrams (Below). Please let us know if you need anything else to get the problem fixed.

Cheers

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Thursday, March 31st, 2011 AT 11:11 PM

JERRYCL

MEMBER
4 POSTS

System leaked to the point where the high pressure side is less than 29 psi. This opens the pressure switch and disconnects the clutch. To get the compressor going again, we have to energize the clutch by bypassing the pressure switch. Have done this before on other makes, but usually the pressure switch is a simple two lead situation. On the Elantra the Koreans have made it a four lead situation, and we are not sure which contacts to jumper.

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Friday, April 1st, 2011 AT 1:21 AM

SATURNTECH9

MECHANIC
30,870 POSTS

There is no need to jump the pressure switch to do what your doing I have never had to do that for charging if its not charging then you have another issue. You will have no idea how much charge you already have in the system so it would be really easy to overcharge it and with the switch bypassed it could get ugly.