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!Originally Posted by RDF1
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.
I'm pretty sure I've seen people just pull out whatever wire was in pin 33, and plugged in the one from the fan to make it work.
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.
How do I go about doing that?
You can download a 2002 calibration file and load it into your 99-00 computer. It will cost you two extra credits.
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.
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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.
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