Last fall I was having climate control trouble. The LED would flash for a couple minutes before it started working and the AC was a little warm. I took it in to the shop to have it checked out and they told me it needed a new high pressure sensor or switch, I don’t remember which they said. I went to the dealership to try and get one so I will be ready for the driving season soon and they had about 3 or 4 sensors and switches they thought it might be. Anyone out there able to point me in the right direction, what the likely part is or how I could trouble shoot this. I would like to avoid paying the diagnostic bill again if it can be helped. By the way this is a 93 with automatic climate control.

Thanks a bunch.

 

Go here and run the Diagnostics first - post any trouble codes:
https://www.corvetteforum.com/techti...=193&TopicID=2

 

Ok finally have some new information. I pulled the code and it was for low Freon. The last time I had the system worked on the put dye in it so I went out and looked under the hood with a UV light and think I found the sensor they told me needs replaced.










Here is one from a bit farther back.















Sorry about the picture quality, my phone makes a bad camera. Anyway I was hoping someone could help me out with a part number or description or anything I can use to get the right part ordered. Thanks a bunch.

 

Looks like the Pressure Sensor since it's mounted on the high side - 3 wire, 5 volt reference from the ECM, 2nd wire return, 3rd wire ground. Should be AC Delco 15-72104. Picture in the catalog at www.acdelco.com - NAPA probably has it too.

 

That looks like it thank you very much.

 

Just thought I would tell you my 92 Experience,
Every spring on the first warm day my Led's would flash also , the Compressor would not come on.
My problem was the system was very slightly low on refrigerant , still had R-12 at the time , anyway adding 1/2 LB of freon , and you must disconnect the battery to erase this problem code for the Climate Control. after that it would be fine for the season.

This high pressure cutoff switch they are trying to sell you only does one thing , It protects the compressor by opening the circuit to the A/C clutch in the event the system pressure exceeds recomended pressure , I think its around 250PSI. only way system pressure goes way up is..

1. Overcharged by someone
2. Cooling fan does not come on in traffic
3. System has a restriction do to a component failure
4. Clogged Orifice tube

I do not believe you need anything but topping off your refrigerant and clearing the memory of the climate control. try it!

Desert

 

Pressure Switch on these later Years does more. It's also used for a/c fan control and it's monitored by the ECM for a pressure (voltage) rise when the compressor engages. A leaking system also allows a little bit to a modest amount of oil to escape with the gas. That creates additional wear on the compressor and the metal it sheds lodges in the orifice which decreases performance and then you're left with deciding: how much oil has it lost? It's better to fix the leak and in this case, replace the switch. It's on a schrader, so you're not going to lose a heck of a lot, though it obviously needs more gas.

 

I don't mean to steal a thread, but is there something like this for 89? My display is freaking out, and
about the only legible thing it ever reads is: 60 or maybe GO?

 

My1992 Fan comes on anytime the A/C control is turned on , doesn't matter what fan speed , I disconnected my high pressure switch and the fan still comes on , that leak at the switch doesn't mean its leaking freon , it could be the schraeder valve , seen it more then a few times.
Anyway I wasn't telling him in my post not to add oil or not , he was asking a switch question , was trying to tell him do not just throw parts on it . ok?

Thats what I love about this forum , you try and talk to someone and relay a personal experience you have on your own Vette(and many others) and there is always someone jumping in tearing down the thread.

Senoir Member's are wondering why people leave this forum and don't come back, HMMMMMM lets see Why?

I guess you are like many repair places that refuse to do any A/C related repairs without , evacuating the system , replaceing parts , recycling the refrigerant with a $10,000 machine , adding oil , and a big bill of $500.00
I'm telling everyone that the majority, not all , but most A/C problems you can quick fix yourself without all that BS.

Desert
ASE Master Automotive/Master Truck /Master Machinist
for over 30 years , yea I'm an IDIOT!

 

It looks like they wanted to sell me the sensor because it is leaking. It is hard to see in the pictures but under the UV light I can see the leak detection dye all over and especially where the wires come out. It did work last season but only for about 2 months blowing cold and got warm as the summer went by. After the LED started flashing is when I took it in to have it checked out and they told me I had a bad sensor, I thought it was not sensing tell I pulled the code for low freon then found it leaking. Thanks for the advice but I think I am going to just replace the sensor and hopefully be done with this for good.

 

Quick question. Over what button is the LED flashing? I noticed the other day that when I started the car the led over the OFF button would flash briefly and then stay on solid. I've check the AC and it seems to put out a good deal of cold and the heat seems to work as well. So, I'm not sure what the flashing LED over the OFF button means. This is on a 91 with automatic climate control.

Thanks, mark

 

If the system is turned off it flashes over the off button, if it is turned on and in auto then that is where it flashes. Basically what ever the system is set to is what flashes.

 

Ok, thanks. So the system is working ok as it should.

Mark

 

No - The '89 has some trouble codes and that would be indicated by a flashing LED at the Outside Temp Readout. Code access is via the Panel. Depress the Outside Temp and Auto Buttons at the same time. A Mode # will appear. Press Warm until it shows 08. Press Cool to retrieve Codes. Codes are 00 - No Faults; 01 Open in the Air Mix Motor circuit; 02 Outside Temp Sensor open; 04 Outside Temp Sensor shorted; 08 Inside Temp Sensor open; and 16 Inside Temp Sensor shorted.

A flashing panel is usually a bad panel and none of those Codes cover anything you describe. Some take it apart and clean up the contacts. Otherwise, a rebuild is usually in order. You could check power and ground first. Ground runs to the Driver's side Kick Panel area and is on a separate lug from the other grounds that meet there. Remove the Hush Panel to access. Ignition Power is from the Gages Fuse which controls a ton of other stuff - like EGR and Vapor Canister Purge, so unless you have some driveability issues, it's probably ok. Memory Power is from the Courtesy Clock Fuse and problems with this circuit are usually indicated by a Control Panel resetting to it's Default value - about 75 degrees, every time you start it up. You might also have problems with other things that are on this circuit; doubt you have anything other than a bad Panel.