98 chevy silverado ac compressor not engaging

Q: What would cause an AC clutch to not engage?

If the clutch doesnt engage, the problem could be a blown fuse, an open in the wire to the clutch coil, a bad clutch coil, a poor ground, or a low pressure lockout. In some vehicles the compressor clutch relay is turned on and off by the low pressure switch and the evaporator temperature sensor.

Q: How do I force my AC compressor to engage?

At the compressors front side, unplug the single wire connector, take a jumper wire and attach it to the wire that you just disconnected from the compressor. Connect the other end of the jumpers wire to the positive terminal of the car battery. This will enable the compressor to start manually.

Q: What do I do if my AC compressor clutch wont engage?

If the compressor clutch doesnt engage; that usually means, theres an electrical or mechanical problem with the compressor. If the AC is not blowing cool air into the car, you may want to do a visual inspection of the AC compressor clutch and determine if you can see what might be causing the clutch to not engage.

Username

Post: Ac compressor clutch not engaging!!!!!!!!!!! (Topic#281734)

koolaid2012
Forum Newbie
Posts: 75

Reg: 05-05-11

Table of Contents Show

What would cause an AC clutch to not engage?
How do I force my AC compressor to engage?
What do I do if my AC compressor clutch wont engage?

User Info

Send Private Topic
View Profile

05-27-12 06:07 PM - Post#2230537

My ac just stopped blowing cold air one day, once I got home the compressor stopped engaging. Checked freon and it was still charged. The ac/heater fuse is not blown. What can cause the clutch to stop engaging?

Email
Report

rockfangd
"9th Year" Gold Supporting Member
Posts: 3209

Age: 36
Loc: Utica ny
Reg: 04-13-10

User Info

Send Private Topic
View Profile

05-27-12 06:47 PM - Post#2230551
In response to koolaid2012

when you say it is still charged can you be more specific.
The system may still have pressure but not enough to engage the compressor. Have you hooked gauges up. If all is good then I would think a pressure switch may have gotten disconnected or gone out

Old School GM fan FOREVER

Email
Report

koolaid2012
Forum Newbie
Posts: 75

Reg: 05-05-11

User Info

Send Private Topic
View Profile

05-27-12 07:29 PM - Post#2230576
In response to rockfangd

On the gauge I have it is in the blue which is around 35 lbs. I think. I have jumpered the low pressure switch connector also, still no luck.

Email
Report

62chevy427
"15th Year" Silver Supporting Member
Posts: 2218

Loc: laurens sc
Reg: 04-13-06

User Info

Send Private Topic
View Profile

05-28-12 06:18 AM - Post#2230690
In response to koolaid2012

35 lbs is a low charge. jumper both high and low switches. you will have to charge the system,too. try to find a leak first. if it is where it can be seen,there usually will be an oily spot. if none can be found,remove the resistors on the blower housing and shine a flashlight on the evap to look for an oily spot.

56 bel air ((since 2002)
62 impala ss (since 1965)
65 el camino (since 1969)
66 nova (since 1987)
67 malibu convertible (since 1981)
72 el camino ss454 (since 1985)
83 gmc 4wd (since 1991)
95 impala (new)
15 chevy equinox

Email
Report

rockfangd
"9th Year" Gold Supporting Member
Posts: 3209

Age: 36
Loc: Utica ny
Reg: 04-13-10

User Info

Send Private Topic
View Profile

05-28-12 07:38 PM - Post#2230943
In response to 62chevy427

35 is low but should be sufficient charge to run the compressor. I like 42-45.
Humor me and pull the comressor fuse and inspect it, if it looks funny replace it. Could be a loss of connection. Also check the ac compressor relay and if questionable switch it out with a known good used one.
Then check the plug at the compressor, inspect it well. that can make all the difference, and if that doesnt work maybe the wire broke in the compressor

Old School GM fan FOREVER

Email
Report

ckjurk
Forum Newbie
Posts: 45

Loc: Texas
Reg: 05-23-12

User Info

Send Private Topic
View Profile

05-28-12 08:11 PM - Post#2230953
In response to rockfangd

When i had this problem, it was a clogged orifice tube, do you have manifold guages, if so i can help you dx

Nothing more satisfying than lying on your back in shorts and a t-shirt working on your truck...
1996 Vortec 5.7L K2500 PU

Email
Report

letsbangout
Contributor
Posts: 151

Reg: 11-29-11

User Info

Send Private Topic
View Profile

05-30-12 09:16 PM - Post#2231704
In response to koolaid2012

Start with the simplest of all: start your truck, turn AC on max. Do you have 12 volts at the compressor connector using it's own ground as a reference? Does the compressor coil have resistance (probably 10 to 100 ohms i'd guess), or is it open (infinite resistance)?

Email
Report

koolaid2012
Forum Newbie
Posts: 75

Reg: 05-05-11

User Info

Send Private Topic
View Profile

05-30-12 11:01 PM - Post#2231719
In response to letsbangout

Well I found the problem it was the connector to the pressure switch, the connecter was getting rusted causing a poor connection. Lucked out I guess I'm just glad I didn't have to pick up a new compressor

Email
Report

What would cause an AC clutch to not engage?

If the clutch doesn't engage, the problem could be a blown fuse, an open in the wire to the clutch coil, a bad clutch coil, a poor ground, or a low pressure lockout. In some vehicles the compressor clutch relay is turned on and off by the low pressure switch and the evaporator temperature sensor.

How do I force my AC compressor to engage?

At the compressor's front side, unplug the single wire connector, take a jumper wire and attach it to the wire that you just disconnected from the compressor. Connect the other end of the jumper's wire to the positive terminal of the car battery. This will enable the compressor to start manually.

What do I do if my AC compressor clutch wont engage?

If the compressor clutch doesn't engage; that usually means, there's an electrical or mechanical problem with the compressor. If the AC is not blowing cool air into the car, you may want to do a visual inspection of the AC compressor clutch and determine if you can see what might be causing the clutch to not engage.