A/C Compressor

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Aug 19, 2007 | 11:42 PM

dhall

Thread Starter

Cruising

Joined: Dec 2005

Posts: 13

Likes: 0

From: Murfreesboro TN

A/C Compressor

While adding freon to my 90 Vette a bunch of wires in the vicinity of the blower motor started smoking. We halted the procedure and and took care of the faulty wiring by wraping them with electrical tape to prevent them from shorting out again. After doing this we proceded to finish adding freon to the system but could not get the compressor to kick in. We checked all the fuses on the left side of dash and all were OK. Is there an inline fuse for the compressor somewhere else? All input will be appreciated. Don

Put Vette in shop and the found a bad relay behind dash by your left knee. There are other relays there also but I forgot what they were. Hope this helps someone else.

Last edited by dhall; Sep 8, 2007 at 02:10 PM. Reason: New Information

Aug 20, 2007 | 04:48 PM

Da Mail Man

Safety Car

Joined: Jul 2004

Posts: 3,835

Likes: 30

Quote:

Originally Posted by dhall

.....do you have a helms field service manual?

Last edited by Da Mail Man; Aug 20, 2007 at 07:30 PM. Reason: spelling

Aug 20, 2007 | 05:13 PM

Yellow2015

Pro

Joined: Sep 2006

Posts: 702

Likes: 2

From: Conyers Ga

Try jumping out the low pressure switch. How do you know it's fully charged? What type of freeon? What are the pressure readings?

Aug 20, 2007 | 06:17 PM

rddaves54

Heel & Toe

Joined: Mar 2004

Posts: 23

Likes: 0

From: Columbia SC

try pulling the fuse to at the accessory fuse and that may reset your compressor

Aug 20, 2007 | 06:20 PM

Da Mail Man

Safety Car

Joined: Jul 2004

Posts: 3,835

Likes: 30

[QUOTE=rddaves54;1561581096]try pulling the fuse to at the accessory fuse and that may reset your compressor[/QUOTE

.....HOW do you "reset" a compressor since it has no memory to retain or reset?.....(you cannot)...

Last edited by Da Mail Man; Aug 20, 2007 at 07:31 PM. Reason: additional info

Aug 20, 2007 | 07:30 PM

Da Mail Man

Safety Car

Joined: Jul 2004

Posts: 3,835

Likes: 30

[QUOTE=InHot;1561582024]

Quote:

Originally Posted by Da Mail Man

You can't.

.....didn't i just tell him that?
edit; that was what i was implying in my original response as i am well aware that you CANNOT..

Last edited by Da Mail Man; Aug 20, 2007 at 07:32 PM. Reason: amended

Aug 20, 2007 | 07:35 PM

SunCr

Le Mans Master

Joined: Dec 2000

Posts: 7,839

Likes: 22

From: San Diego, Ca

'90 is driven by the ECM - ie, with an a/c request signal, the ECM grounds the compressor relay. ECM also monitors the low pressure switch which opens when the pressure is low enough to cause icing OR when the charge is too low which causes rapid cycling of the compressor clutch. If the latter condition occurs, the ECM senses a low charge condition, a trouble code is set, and it won't drive the Compressor Relay until the code is cleared. Do that by disconnecting and reconnecting the battery.

Can you be more specific about the wiring that shorted? If it's the Blower Harness, that often happens if the Motor has a dead short or due to age, it's draw exceeds the ampacity of the wiring. In addition, the harness terminals are crimped and they can loosen with age causing a voltage drop. That causes the wires to heat up and when they get hot enough, they simply melt and open the circuit. Repair by opening up the WeatherPak (it probably needs to be replaced) and soldering the terminals to the wires. Replacing the blower motor might not be a bad idea either, assuming this is the harness with the problem.

Aug 23, 2007 | 02:04 AM

dhall

Thread Starter

Cruising

Joined: Dec 2005

Posts: 13

Likes: 0

From: Murfreesboro TN

The wires shorted out and and the compressor shut down and I am assuming that the system is not fully charged because it did not take a full can of freon.