OBD Port Question

[driver456]

I have a 97 C5 auto I have the dreaded blinking a/c light.Freon is good,Pressure is good.When I hook up the scan tool and go to bidirectional then control panel and click on a/c on the control panel my a/c works fine,No blinking light,The light stays on on the a/c button,Ice cold a/c,No problems.My question is,Does it bypass the PCM,What wires in the OBD port does it use to turn on the a/c.Does it ground it out or send voltage.Would anybody have a wiring diagram from the OBD port to the HVAC system.I'm just trying to narrow it down.....Thanks..........Paul

[lsxtech]

its grounding it though the pcm, not the OBD connector, something is keeping your pcm from turning the a/c on if it works with the bidirectional control

[lsxtech]

I believe the vettes have a evaporator temp sensor, if you pressures are good and switches are good i would look at the evap sensor

[driver456]

I believe the vettes have a evaporator temp sensor, if you pressures are good and switches are good i would look at the evap sensor
Would you know where that is?...............Paul

[lsxtech]

have you scanned it for any codes

[driver456]

have you scanned it for any codes
Yes,No codes.............Paul

[lsxtech]

locate evaporator should have wires coming out of the box somewhere that go to a connector, i'm not at the shop right now so i can't look up the exact location of the connector, but if you can wait till tomorrow i will get all the info you need

[driver456]

locate evaporator should have wires coming out of the box somewhere that go to a connector, i'm not at the shop right now so i can't look up the exact location of the connector, but if you can wait till tomorrow i will get all the info you need
That would be awsome dude,I'll wait.....Thank you...............Paul :cheers:

[mnotx]

I have the GM online manual. Let me know if you need any of the diagnostic or repair procedures. I can send anything you want by e-mail. Just let me know what you need.

Also, is the HVAC automatic or manual?

Milt,
mnotx@grandecom.net

[driver456]

I have the GM online manual. Let me know if you need any of the diagnostic or repair procedures. I can send anything you want by e-mail. Just let me know what you need.

Also, is the HVAC automatic or manual?

Milt,
mnotx@grandecom.net
I'm not sure what you mean about the HVAC being auto or manual.Its a dual zone,I know that.I have the 4 manuals,But I couldn't find anything with the OBD port.Lsxtech kind of answerd one of my questions.I'm just trying to narrow it down,Maybe someone will come up with an answer:Eyecrazy:......thank you ...................Paul

[mnotx]

Sounds like an auto. The manual doesn't have the features that let you set a specific temp and leave it, nor the dual zone if I remember correctly. You have to turn the fan speed up or down manually, etc.

Didn't know you had the manuals. Guess you already checked the wiring schematics and tried the diagnostic procedures and they didn't help. Bummer. Good luck!

Let us know what you find. It'll happen to one of us eventually.