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Thread: 0411 Swap - Electric Fan won't shut off when it should

  1. #1
    Advanced Tuner Obsolete489's Avatar
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    0411 Swap - Electric Fan won't shut off when it should

    Alright guys, another 0411 issues. So I'm trying out a mark VIII fan in my pickup, I'm not sure yet if it'll flow enough air to keep it but we'll see. Anyway, the fan turns on properly with the ECT I set it at, but after the first time it comes on it won't turn back off at my speed or ECT shutoff, the only way to get it to shut off is the the scanner controls.

    Vehicle Information:
    2000 K2500
    Gen 6 489 CID
    0411 out of an 01 suburban, which i think did a "write entire" over to get the 12212156 OS

    In the log:
    Fan on at 2.5 minutes in

    At about 11 minutes I hit the highway and consistently stay above the speed set point, a bit later I shut the fan off manually.
    I didn't drop below the ect set point in this log, but I've had it happen other times and the fan stays on.

    fans wont shut off.hpl 489 Tune - Fan Wont Shut Off.hpt

    Any thoughts? Wouldn't be something weird with the AC settings would it? Thanks for any help.
    2000 K2500 - 489 CI Vortec w/ comp XE270 cam - 0411 swap and rear mount turbo
    1972 M35a2
    2011 LML Duramax

  2. #2
    Advanced Tuner Obsolete489's Avatar
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    Are the off conditions ECT & speed, not just one or the other? It shut off today when I hit 35 and my ect got back down to 198, so maybe I'm just an idiot lol I thought i tried that. I will raise the off ect, and see what that yields me next time I drive it.
    2000 K2500 - 489 CI Vortec w/ comp XE270 cam - 0411 swap and rear mount turbo
    1972 M35a2
    2011 LML Duramax

  3. #3
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    Ect, vehicle speed and a/c pressure. only if you have an a/c pressure sensor wired to the pcm. Check the fan on run time make sure you have it set to something reasonable, maybe 30 seconds or so after the ect off temp is met.
    97 ext cab short bed silverado 5.7 411 swap, edelbrock 29135 intake, lightly ported 906 heads milled .035 thou. factory press in rocker studs & rockers, comp 787 retainers & stock locks, ls6 springs. Comp cams 08-503-8 T56 swap

    86 SWB crate vortec 5.7/th350 The wife's truck

  4. #4
    Advanced Tuner Obsolete489's Avatar
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    I do not have a pressure sensor wired in, so I wasn't really sure what to do with the pressure settings. The disable delay time was only like 1 second, min time was at 50 seconds, i'll switch it to 30 and see how that works.
    2000 K2500 - 489 CI Vortec w/ comp XE270 cam - 0411 swap and rear mount turbo
    1972 M35a2
    2011 LML Duramax

  5. #5
    Advanced Tuner Obsolete489's Avatar
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    Seems like its working, mostly anyway. The disable speed seem to do anything, but the ect disable does seem to be working at least.
    2000 K2500 - 489 CI Vortec w/ comp XE270 cam - 0411 swap and rear mount turbo
    1972 M35a2
    2011 LML Duramax

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    I might be wrong but I think disable speed works with a/c enabled. Since your high side pressure will drop with vehicle speed. The disable speed function will keep the fan from pulling the high side pressures to low and causing rapid cycling of the compressor.

    Since you do not have a pressure switch wired to the pcm. you only need to worry about the high side pressure getting to high while sitting idle with the fan off. I keep a separate ground circuit to switch the fan to ign on. For those 110* west Texas days.
    97 ext cab short bed silverado 5.7 411 swap, edelbrock 29135 intake, lightly ported 906 heads milled .035 thou. factory press in rocker studs & rockers, comp 787 retainers & stock locks, ls6 springs. Comp cams 08-503-8 T56 swap

    86 SWB crate vortec 5.7/th350 The wife's truck

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    Advanced Tuner Obsolete489's Avatar
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    I bet you're right about that, would probably be worth adding a backup switch in like you did though. If it was that hot here, I'm sure the fan would be on anyway haha. I'm curious to see how well it can keep up when it gets hot this summer.
    2000 K2500 - 489 CI Vortec w/ comp XE270 cam - 0411 swap and rear mount turbo
    1972 M35a2
    2011 LML Duramax

  8. #8
    Advanced Tuner Obsolete489's Avatar
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    Little late to be updating this, but to anyone curious the mark VIII fan will not keep up with any sort of load on my truck. Highway cruising was fine, seemed to keep cool at idle and low speed, but when i tried pulling a 10k skid loader it would not keep up at all.
    2000 K2500 - 489 CI Vortec w/ comp XE270 cam - 0411 swap and rear mount turbo
    1972 M35a2
    2011 LML Duramax

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    Quote Originally Posted by Obsolete489 View Post
    Little late to be updating this, but to anyone curious the mark VIII fan will not keep up with any sort of load on my truck. Highway cruising was fine, seemed to keep cool at idle and low speed, but when i tried pulling a 10k skid loader it would not keep up at all.

    so what did you do?