Trailblazer E40 Question

[AlanDC]

With only a single wire from the ECM, you'll only be able to get all fans on at 100% or all fans off, no matter how many relays or fans you have. Is that what you're wanting?

Yes, that's how I have configured my Gen III L33 swap and it works well.

[blindsquirrel]

OK, so there's an edited diagram for single-stage fan(s) in post #2. Copy GTO fan settings bit-for-bit, even though GTO originally used 2-stage/3-relay setup, and it will 'just work'. The GTO has Output #1 grounded any time any fan is commanded on in either low or high speed, so a single-relay setup won't know or care that there's another ECM pin that's not connected to anything.

[AlanDC]

OK, so there's an edited diagram for single-stage fan(s) in post #2. Copy GTO fan settings bit-for-bit, even though GTO originally used 2-stage/3-relay setup, and it will 'just work'. The GTO has Output #1 grounded any time any fan is commanded on in either low or high speed, so a single-relay setup won't know or care that there's another ECM pin that's not connected to anything.

Thanks. Where can I find the right GTO calibration to copy the values?

[blindsquirrel]

https://www.hptuners.com/my-account/tunerepository/ (unless they helpfully redirect you to a country-specific site that has no files uploaded)

[AlanDC]

https://www.hptuners.com/my-account/tunerepository/ (unless they helpfully redirect you to a country-specific site that has no files uploaded)

Thanks a lot for your help. I?ve found a 2005 GTO calibration file using a e40 ECM. I?ll do all the suggested changes and wiring and give it a try.

From this table, I guess if I want the fan relay kicks in at a lower temp, I must put a 91 at a lower temp in this table:

Temps config.png