I think I got the AC all figured out but need someone to verify if I got it correct. I don’t want to fry anything!

My 1998 Sonoma/S10 now has 5.3 V8 with a Denso compressor. I believe the 5.3 trucks uses a Low Pressure cycling switch to control the AC accumulator. My 1998 Sonoma/S10 originally had 4-Cylinder and I believe it had a V7 Variable Displacement AC Compressor operated by 3 wire trinary pressure sensor that is mounted on the high-pressure line for full PCM control. Therefore, the S10 4-Cylinder did not use a Low Pressure Cycling Switch. It looks like the V6 S10 had a different A/C compressor and it did use a Low Pressure cycling switch to control the AC compressor mounted on the accumulator I believe.

Can someone please confirm the following?

The S10 PCM is looking for a +12V for A/C request on Pin 36. Correct?

The 5.3 PCM is looking for a +12V for A/C request on Pin 17. Correct?

On 5.3, the High-Pressure Cutoff Switch is on the back of the compressor. Correct?

On 5.3, the Low Pressure Cycling Switch is mounted on the AC accumulator. Correct?

On 5.3, I can delete the A/C Automatic Recirculating Switch Pin 11-C2. Correct?

My 5.3 411 PCM was flashed and I am driving a single electric fan from Pin 42-C1. I believe the Fan #2 will work with Pin 33-C2. When AC is requested, does the PCM fires both Fan 1 and 2?

The A/C Compressor Low Pressure Cycling Switch for both 5.3 and the S10 V6 have same M12-1.5mm threads (with different connector) and about same pressure ratings so the 5.3 switch should bolt right on the S10 V6 Accumulator.

I should be able to use the S10 V6 A/C Accumulator with 5.3 Denso Compressor and 5.3 Low Pressure Cycling Switch. Correct?

Thank you!

Waid

 

On my OBS, I determined that Pin 55 needs to see ground. Originally a pressure switch was there. I grounded mine.

But, I'm getting a steady 7 seconds ON and 15 Seconds OFF compressor cycle that I think is because there's nothing connected to pin 11.

If you figure it out, please let me know.

https://ls1tech.com/forums/conversio...l#post20050950

Thanks,

-KP

 

Is Pin 17 on 5.3 PCM looking for +12V for AC Request ?

Thanks

 

Yes. Near as I can tell.

Pin 55 was 1 pair of sensors. Accumulator (Whatever that switch is called) and Low Pressure at the Compressor?

Pin 11 was the High Pressure Switch.

There's lots of diagrams posted on my thread.

-KP

 

Apparently, some OBS's had 3 'pressure' switches for the A/C. There were 2 on the Compressor and the Accumulator. I think.





I believe that explains these connectors:



I'd have guessed those went on the Compressor, except they fit on the Accumulator. If you look closely, you can see they're 'clocked' a little differently.

I haven't really seen my (intact) OBS Harness since 2010, so it's starting to lose clarity.

-KP