Automotive Air Conditioning Information Forum (Archives)

jas on Wed July 06, 2011 6:35 AM

Year: 2003
Make: Pontiac
Model: Montana
Engine Size: 3.4
Refrigerant Type: R134a
Country of Origin: France

Hi

All apologies for my bad english.

Alone un France with my 03' Venture A/C went out suddently.

The facts :

My mechanic change :
- new AC Delco compressor (comes with clutch)
- new pressure sensor
- new R134a

Tests done :
- pressure : OK
- all fuses : OK.
- relay OK. (A/C clutch relay is the same as the horn relay, I swapped them around (with the van off) and tried again : A/C clutch doesnt works but the horn does.)
- fan 1, fan2 and fan common relay : ok.
- clutch test : I hear a click sound of clutch when I hot wire the contacts of the clutch relay circuit (87 & 30). The AC works, it blows cold.
- BUT no signal comes from the inside command : no signal (85 -> 86).



I own the Haynes with wiring diagram but I dont have any ideas to look for.

Thank you for your help

JAS

GM Tech on Wed July 06, 2011 7:51 AM

problem is upstream from relay---obviously.....so measure return voltage on pressure transducer 3 wire connector--one wire should be 5 volt, one should be ground, and one should be 1 volt or less (static pressure considered).......

Control head okay? a/c button lit? nothing flashing upon engine start-up?

-------------------------
The number one A/C diagnostic tool there is- is to know how much refrigerant is in the system- this can only be done by recovering and weighing the refrigerant!!
Just a thought.... 65% of A/C failures in my 3200 car diagnostic database (GM vehicles) are due to loss of refrigerant due to a leak......

jas on Wed July 06, 2011 8:03 AM

> measure return voltage on pressure transducer 3 wire connector
Where is it located ?

>--one wire should be 5 volt, one should be ground, and one should be 1 volt or less (static pressure considered).......
Okay I will measure it after the #1 answer ;-)

>Control head okay?
Duno

>a/c button lit?
Yes

>nothing flashing upon engine start-up?
No

Thank you.

JAS