Home page

Cool! NEW FEATURE! Add "Your Corvette Story" today

C4 Cooling and Heating Systems

1990 AC problems from Ottawa Canada (1/2)
 7/17/18 11:03am
Willy
Standard Member
Send Private Message

, - Canada

Vette(s):
1990 Steel Blue Metallic coupe


Joined: 8/29/2015
Posts: 3

AC stopped working after EGR valve replaced
My son a ford mechanic spent 4 hours and came up with the following
All fuses OK, Previously when grounded the AC Relay in dash AC worked
Now seems to be an issue with low pressure cut off switch. Have to bypass now to make AC work when jumping relay.
Wire coming from heater/AC programmer to ECM - cut wire and 5v when AC on 2.5v when off (selected from head unit)On the ECM side 13.65 v all the time
Reconnect wire 13-10 v -  not really charging when A/C selector pressed on head unit.  Is it a pinched wire? Near intake manifold? He got frustrated - ECM not grounding AC relay because of this 13 v
Any help, tips would be appreciated.



______________
Our Sponsors help support C4VR
Sponsor Ad

Re: 1990 AC problems from Ottawa Canada (2/2)
 8/7/18 2:50pm
Willy
Standard Member
Send Private Message

, - Canada

Vette(s):
1990 Steel Blue Metallic coupe


Joined: 8/29/2015
Posts: 3

Programmer unit gone and has been sent to Corvette Central for rebuild + new pressure cycling switch - Will let you know if all fixed and when

______________