You can cut the pin 33 wire and use it to trigger a relay.
They pcm outputs are ground trigger. do you have 12 Volts at the relay pin 30 and 85?
Change ECM 8034 to a lower number (50*F) and fan Low will trigger with it sees AC request.
You can cut the pin 33 wire and use it to trigger a relay.
They pcm outputs are ground trigger. do you have 12 Volts at the relay pin 30 and 85?
Change ECM 8034 to a lower number (50*F) and fan Low will trigger with it sees AC request.
Thank you for the response!
I currently have the blue wire (originally intended for pin 33) hooked up to a relay the is triggered by the AC clutch circuit. The only problem I am having is the fans will turn on and stay on as soon as the truck is started.
I originally had the blue wire hooked up to pin 33 and changed ECM 750 from AC recirc to Fan #2 but it didn't seem work correctly. I may have had something else screwed up though since this is the first time I have run into this problem.
That was the way I originally wired it but still had the same problem. Fans are just running on low all the time
Years ago i remember having this issue with a 99 and a 2000 truck. Upgrading to a 2002 operating system fixed the issue.
When you do this, do you write entire?
And does this work across models too? Could he write a calibration file from a 2002 Tahoe instead of a 2002 Silverado? (given that it's the exact same engine/PCM).
Yes. You must use the Write Entire option. A 2002 Tahoe file will work as well. Just bear in mind that some of the 02 Tahoe's were flex fuel, so they had the 33 lb/hr flex injectors. Some of the 02 Tahoe's were DBW as well. Both of those things can easily be changed in the tune though.
I do these routinely with 99-00 operating systems. You might want to post your tune file/go over your schematic to see if you missed something simple.
Tuner at PCMofnc.com
Email tuning!!!, Mail order, Dyno tuning, Performance Parts, Electric Fan Kits, 4l80e swap harnesses, 6l80 -> 4l80e conversion harnesses, Installs
Sorry to resurrect this thread but im doing the efan conversion on a 1999 Silverado 1500 4.8/4l60e 2wd. Used an 05 Silverado harness and fan assembly. Plus a BP automotive 1018 kit to give the PCM pressure readings. I can turn both fans on in VCM scanner but cant get them to turn on by temperature readings. Would someone look at my settings and see if I have missed something? i am using the stock 896 PCM.