A/C programmer.

[rlg]

A/C clutch does not engage.

Changed A/C clutch relay, that's not it.

No voltage to any of the system.

No codes of any kind. The A/C head unit shows no codes.

If the A/C programmer is bad would it throw a code somewhere?

Clutch works with direct 12 volts.

The defrost button does not send the air to the defrost vents.


anyway to check the programmer??

 

[gw962]

Unfortunately, the FSM shows that you need a Tech scanner to check out the programmer.
I'm having the same issues on my '90 also. No codes...jumper the pressure cycle switch and the compressor engages....I guess it's time for a trip to an AC shop.

 

[G Winter]

Did you try bypassing the pressure switch?

Glenn

 

[rlg]

Glenn,

I tried shorting all three switches.

the only way the clutch will engage is with 12 volts directly.

it is not getting 12 volts to any of the switches.

Thanks

Bob

 

[jmccloud]

No A/C compressor voltage

Which A/C do you have, C68 automatic temp control or C60 manual control?
My '95 with C60 manual control had voltage to the compressor all of the time; except when the outside temp got cold and the low pressure switch opened up.
The FSM showed a rotary switch in the control head (in the dash) but the control head actually had transistor switches to choose where the air directed and whether the compressor was activated (remember, I have manual A/C). Go figure.
Anyway, the transistor that switched the compressor on/off was shorted and kept 12v to the compressor all of the time.
If your control head has an open circuit transistor, it will never get 12v.
Again, even if you have C60 manual control, a different blown transistor could keep the air from being directed to the defrost vents.
Good luck.
PS A frequent failure mode is for air only out the defrost vents and the floor. This can be caused by poor vacuum or a shot or leaky controller. Since you can not get air out of the defrost, you likely do not have the leaky vacuum or shot controller problem. Search and there's a lot of info there.

 

[rlg]

I have the C68

 

[rlg]

I also checked for codes at the control head and it showed nothing wrong in the 00 check.

 

[jmccloud]

Compressor won't run

Do a search on cleaning the control head contacts. There is a lot of info.
I'd post it but don't recall the details. Basically it could be a contacts problem that's inexpensively cured but with significant dis-assembly of the dash.
The info regarding the transistors possibly being bad probably applies to the C68 auto climate control as well.
Good luck
PS here's one search result
http://www.corvetteactioncenter.com...ormance/86753-89-climate-control-problem.html

 

[larryfs]

I have a 96 programmer..
$100

 

[lfalzarano]

1990 ERlectronic Standard Corvette AC Programer

The answer is the 1990 electonic AC programmer was a one year part. Go to this site below to get your electronic AC programmer. Part Number is 88961234 for the 1990 standard Corvette. I beleive the OEM part number was 1228331

AutoEcms.com 877-687-3267