C4 Tech/Performance L98 Corvette and LT1 Corvette Technical Info, Internal Engine, External Engine

A/C Clutch Not engaging

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Old 07-05-2018, 12:33 PM
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belairbrian
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Default A/C Clutch Not engaging

92 LT1 Coupe. A/C has been working fine before today.

The A/C stopped making cold air. Auto light was flashing instead of steady. Turned system off and Off light was Flashing. Then quit flashing. Pressed Auto again and Auto light was on steady, but no cold air. Parked and opened the hood and the compressor was not engaged.

Here's what I know so far.
I do not have 12v to the clutch connector with the system on in auto, temp set to 65.
Put the gauges on and with compressor not running low side maxed out the gauge.
The car was converted to R134a at some point prior to me purchasing. High side fitting is where I would expect. The low side is on the dryer. Is this normal?

The troubleshooting diagram requires a tech 1 for most of the steps which I don't have. Anyone have a set of troubleshooting steps that don't require a tech 1?

Old 07-05-2018, 12:43 PM
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81c3
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Originally Posted by belairbrian
92 LT1 Coupe. A/C has been working fine before today.

The A/C stopped making cold air. Auto light was flashing instead of steady. Turned system off and Off light was Flashing. Then quit flashing. Pressed Auto again and Auto light was on steady, but no cold air. Parked and opened the hood and the compressor was not engaged.

Here's what I know so far.
I do not have 12v to the clutch connector with the system on in auto, temp set to 65.
Put the gauges on and with compressor not running low side maxed out the gauge.
The car was converted to R134a at some point prior to me purchasing. High side fitting is where I would expect. The low side is on the dryer. Is this normal?

The troubleshooting diagram requires a tech 1 for most of the steps which I don't have. Anyone have a set of troubleshooting steps that don't require a tech 1?
Press the up/down fan speed for 5 seconds and it will show 00 then press the button in the middle, it will show a code. That will give you more direction.... And yes, the low side fitting is on the dryer on mine also..I just was messing with mine yesterday....

Last edited by 81c3; 07-05-2018 at 12:45 PM.
Old 07-05-2018, 01:02 PM
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WVZR-1
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See 1C-1-3 and the following few for the diagnostic codes with C68. It's NOT an 'answer all' but it's there so use it.

Last edited by WVZR-1; 07-05-2018 at 01:03 PM.
Old 07-06-2018, 12:23 AM
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PatternDayTrader
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You don't need the tech1 for this job.
​​​You need a wiring schematic. It's probably something stupid like the low side switch is bad or the fuse has blown.

Last edited by PatternDayTrader; 07-06-2018 at 12:24 AM.
Old 07-06-2018, 09:20 AM
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belairbrian
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Hi guys thanks for the inputs. I ran the diagnostic and it returned a 09 code (low Freon). I jumpered the compressor at the relay, put the gauges on and was around 21/210 at 2000 rpms. I added some 134, and brought it up to 34/250 and the system started working.

With a thermometer in the center dash vents I was seeing 41-45 F on a 10 mile test drive at 88 ambient.
At some point dye had been put in as I had some at the high side fitting. There was avery faint indication at the switch on the low side pipe by the evap housing. SO may need to look at that.
Old 07-06-2018, 12:30 PM
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billschroeder5842
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Originally Posted by belairbrian
With a thermometer in the center dash vents I was seeing 41-45 F on a 10 mile test drive at 88 ambient.
.
I had the identical problem... 09. Freon (134a) and my 91 came back to life. My blows ar 42 with the car "cool" sitting in the Texas sun and I can't get ti to blow below 52. Too much glass on these C4s I suppose?
Old 07-06-2018, 02:17 PM
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belairbrian
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Originally Posted by billschroeder5842
I had the identical problem... 09. Freon (134a) and my 91 came back to life. My blows ar 42 with the car "cool" sitting in the Texas sun and I can't get ti to blow below 52. Too much glass on these C4s I suppose?
Bill.
It gets hot in Texas? Didn't notice it Marching around Lackland one July in my youth.

Mine is sitting outside in the sun right now it's 91 (heat index 98). I'll see what she reads at the vent on the way home.

Believe it or not my Acura MDX is worse when it sits. You can't touch the steering wheel even if there is a sun shade on the windshield. But try and drive ten miles with the AC on full and you'll freeze yourself out.
Old 07-06-2018, 03:07 PM
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90+ degrees, blower on low ac on recirculate.
Old 07-06-2018, 05:34 PM
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Here's some pics of what I had this afternoon. The temp gauge is in the center dash vent above the DIC.


OAT at key on


duct temp at key on


1 mile later


Low as it got


Engine temp 196
Old 07-06-2018, 08:26 PM
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Originally Posted by PatternDayTrader


90+ degrees, blower on low ac on recirculate.
PDT... As my teenage daughter would say "I'm so jealous "i hate you!"
Old 07-06-2018, 09:25 PM
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Lol …

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