Jump to content

Electric Cooling fans staying ON with engine is OFF.

tonyblaze

Recommended Posts

tonyblaze New Member

tonyblaze

Posted
Posted

I have a 2005 GMC 1500 Sierra 5.3 with the dual electric fans. The truck has 205K miles on it, and it has been a good truck. I bought it new in 2005.

This past week, I had to jump start the truck, since the battery was dead. After jumping it off and driving it, I got home and noticed the electric fans staying on after the engine is off and keys out of the switch. So that drained my battery.

Today, I replaced all 3 relays and the temperature sensor on the driver's side head. Well, it did not fix the problem, the fans are still running.

Does any know what I need to do next? Is there another sensor or control module for the fans?

Badass69 Senior Enthusiast

Badass69

Posted
Posted

It's just 2 trigger pins from the pcm that operate the fans. Al the pcm does is ground one or the other or both depending on desired speed. Sounds like you either physically damaged something or screwed up the pcm thus it is grounding at least one of the triggers constantly. Blue connector number 33 and green number 42.

PH-Wolf Enthusiast

PH-Wolf

Posted
Posted

It is quite possible the ECM is malfunctioning, Since you replaced the temp sensor, relays, I'd check the connections and wiring making sure its not rubbed threw and feeding off other wire or grounding out,(Seen that before) Also test the ECM for any internal issues, I've seen this once a couple years ago where the ECM was malfunctioning and commanding the fans to be on all the time due to the ECM thinking the coolant temp was high and it was not, reading 235 degrees(truck was sitting overnight in the shop), Temp sensor/wiring was fine, found the ECM to be at fault and had to replace the ECM.

Archived

This topic is now archived and is closed to further replies.

Go to topic listing

  • Recently Browsing   0 members

    • No registered users viewing this page.

  • Forum Statistics

    250.4k
    Total Topics
    2.7m
    Total Posts

  • Member Statistics

    342,840
    Total Members
    8,960
    Most Online
    appletrav
    Newest Member
    appletrav
    Joined

  • Who's Online   5 Members, 0 Anonymous, 356 Guests (See full list)

  • Latest Articles

  • Posts

    • newdude
      2 speed transfer case optional now?

      By newdude · Posted

      This is a 1/2 ton thing ONLY.  All HDs 2020-2026 have the two speed transfer case, with Autotrac as an option.     1/2 tons 2019-2026, regular 4x4s come with a single speed case (no 4LO!), and trucks with Z71 ordered, or all Trail Boss trucks come with the 2 speed case.  2 speed case is also an option on WT, and is also standard on High Country.  
    • newdude
      Different requirements for oil filters?

      By newdude · Posted

      2013 5.3 still to this day calls for the PF48 filter.  Which as a 15psi bypass pressure.     There is a TSB, 17-NA-157 that talks about the PF-63 and PF-64 filters which have a higher bypass rating of 22psi.    TSB HERE - temp.xml   "Beginning in 2012, the oil pumps began to regulate main gallery feedback instead of pump out pressure. This means that the oil pump now does not begin to regulate until pressure is built up to the main gallery. This change reduces the amount of time it takes to provide oil to the engine bearing and lifters during extreme cold start conditions.  Main gallery feedback oil pump control systems are present on the following engine families which use Spin-on oil filters: Small Gas Engine (SGE), Large Gas Engine (LGE), High Feature (HFV6) Gen2 and Small Block Gen5 gasoline engines. These engines with the main gallery feedback oil pump control systems are factory built with an ACDelco® oil filters"   It also calls out what engines use those filters.  The gen 4 small blocks were not on that list (LMG, LC9, L9H, L92, L94, L20, L96).  Gen 5 small blocks use the higher pressure filter.          That all said...   Your 7045 Napa filter is the PF63 equivalent, with 22psi bypass.  You are already using the higher bypass pressure filter.  You CAN keep using it, you don't technically have to use it though.  
    • Grumpy Bear
      Different requirements for oil filters?

      By Grumpy Bear · Posted

      Do you know WHY the filter relief setting was increased to 22 psig?    When the new system goes into the second stage the pump volume ramps up considerably. It was found that the 15 psi filter bypass setting put the filter in bypass on a warm engine when the second stage was activated. Raising the filter bypass setting forced the filter to do what it designed to do. Filter. Preventing debris from circulating during high load, high rpm operation.    So next question is how did GM find this out? VLOM/lifter failures and a deep dive by Melling Corp.    Last question. Is it required? Look at it like this; a motor may be equipped with a rev limiter. But it only works if the set point in reached. That 22 psig setting only matters if the pressure differential across the filter media exceeds 15 psig during normal warm operation. Second stage kicks in around 3000-3500 rpm.    I can't answer your question because I don't know you and how you use the truck. But I think there is enough information here to let you decide for yourself. 😉
    • Coastie05
      give me some tips to make my truck look better

      By Coastie05 · Posted

      Go back to OEM wheels. 
    • newdude
      2020 Trailboss 6.2 replacement

      By newdude · Posted

      Probably not their first rodeo, so it should go as planned most likely.  Typically the service manager or tech doing the swap will put some seat time to shake it down after they get it all put back together.  We usually put 50-100mi before we hand them back so if something happens, its not after you get it.  A coolant leaks, oil leaks, a ground left off or loose, vibration, etc.     The new engines so far have been good?  There's been a couple that have popped out there again (the replacement engine) but most have been okay.  

  • GM-Trucks.com Clubs

  • Popular Contributors

×
×
  • Create New...