How do I wire the A/C compressor to work with the LS ECM on an 87 swap?
Here is what the documentation says. Each point links to its source; details depend on your exact computer, harness and transmission.
Other wiring
- P01/P59; Gen III LS; 1999-2007: PSI standalone harnesses provide a white A/C Request wire at the PCM connector that should see 12 volts when the A/C is turned on. (PSI Conversion / Performance Systems Integration (via SlideShare))
Computer and tune
- P01, P59; 2000-2005: Between 2000 and 2005 GM used both mechanical (cable) and drive-by-wire throttle control; a cable-throttle ECU can be used on a drive-by-wire engine only if the complete operating system of the ECU is re-flashed. LSX Magazine also cautions never to start an engine with an ECM whose programming is unknown. (LSX Magazine)
Confirm against the instructions for your exact parts before wiring. More: Other wiring in our tuning guide.
Confidence: medium — sources disagree or are limited; check the sources below.
Community discussion
Related questions
- Best LS swap wiring harness
- Stock PCM vs Holley Terminator X for an LS swap
- How do I tune an LS swap? (HP Tuners basics)
- How to make a standalone LS wiring harness
- VATS delete: what it is and how to do it
- Drive-by-wire vs cable throttle for an LS swap
Sources
- Solving ECU Options For Your LT Or LS Engine Swap With EFILive — LSX Magazine
- PSI HAR-1058 LS2/LS3 Standalone Harness Instructions (MAN-1058) — PSI Conversion / Performance Systems Integration (via SlideShare)