A/C clutch will not run unless it is jumped at relay or low-pressure switch?

DAN HOOKS

MEMBER
1997 CHEVROLET SILVERADO
7.4L
V8
AUTOMATIC
178,000 MILES

The A/C was charged, and I turned on clutch on via me jumping the relay on the fuse box to make clutch come on, low temperature sensor was replaced and relay changed, but clutch still won't run unless its jumped at relay or low-pressure switch.

7 Replies

KEN L

MASTER CERTIFIED MECHANIC
47,574 POSTS

The low-pressure switch could be telling you there is a leak in the system. Can I ask if you jump the relay, and the compressor runs does it make cold air? When you had the system charged was it flat or did you do it yourself? Let's see if there is any refrigerant left in the system by following this guide:

https://youtu.be/-mikngtS63w?si=JX-3esKd7xCz5jwn

This guide can help as well:

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

Please go over these guides and get back to us.

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Friday, July 19th, 2024 AT 12:28 PM

DAN HOOKS

MEMBER
11 POSTS

It has Freon in system 135 H 55 L.@ 85° Its Cold 41°` when I jump ether one, low pressure switch or relay. System blew a line from a over charge 3 years ago. I just now replaced the line and pulled a vacuum, it held, I charged System. Clutch refuses to run unless jumped. It gets cold if I jump relay or low pressure switch.

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Friday, July 19th, 2024 AT 9:19 PM

KEN L