@ScottyBoy you seem to be very knowledgeable on these fan swaps! I did this conversion about 3 years ago on my 03 Tahoe. My fans run all of the time (driving down the road and in winter on cold start ups). All factory parts came from a junkyard 05 Tahoe. Install was very straightforward annd simple until I pinned the ecm plug. I sent my ecm into a guy named Jesse that specializes in the fan swaps (everyone online swears by this guy). I can get more info on him if needed. He now owns a business and does a lot of different programming. I installed my programmed ecm and the fan run constantly. I switched the ecm pins and still runs consistently. I changed all relays and fuses in the factory fuse box purchased on eBay and no difference. I believe it’s a programming issue so I contacted Jesse. He assured me it’s not programming. So my question to you is what do you believe might be my problem? In my opinion the only other thing I can do is send my ecm somewhere else and have it reprogrammed to make sure thats not the problem.
Electric Fan Conversion Question
- Thread starter Dantheman-2003
- Start date
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mattbta
Full Access Member
@Jkpii2000
Is your temp gauge on the dash functioning correctly? Use a scan tool and see what your engine coolant temp sensor is reporting. The default protect mode for a bad ECT is fans on all the time. That's an easy first step.
Is your temp gauge on the dash functioning correctly? Use a scan tool and see what your engine coolant temp sensor is reporting. The default protect mode for a bad ECT is fans on all the time. That's an easy first step.
I will check that thank you but I did replace both sensors about a year ago.
Have the fans run all of the time since they were installed and the engine computer was programmed for the fans? Or is this a recent development?
What do you mean by "switched the pins" on the engine computer? Swapping pin locations, or replacing the pins and leaving the wiring on the same pins?
What do you mean by "switched the pins" on the engine computer? Swapping pin locations, or replacing the pins and leaving the wiring on the same pins?
Tonyrodz
Resident Resident
I've had sensors be bad right out of the box.
ScottyBoy
Full Access Member
If you can definitely confirm 100% that the coolant temp sensor is NOT defective, and that the pins are in the proper spots, and the harness is DEFINITELY not damaged (scraped, pinched wires ANYWHERE) then I would start to suspect that your guy didn't program it properly.
ScottyBoy
Full Access Member
And I should have clarified about the harness being damaged. If the vehicle the harness came from was in a collision (even a minor collision) then the wires can become so pinched together that the insulation is compromised and the conductors can be touching. So if one of the trigger wires is damaged and the ground wire is damaged, and the two are touching, then that would cause a constant fan on situation. This is why when I pull harnesses and sell them to people, I thoroughly clean, inspect, and test every wire in the harness, and perform any repairs if needed. Sometimes it may be replacing a few inches of wire, sometimes it's as simple as covering damaged insulation with some marine grade heat shrink tubing ( the kind with glue on the inside of it).
So before calling out your tuner, I'd check the harness and check the coolant temp sensor. A quick and easy way to test the harness would be to unplug both trigger pins from the ECM, and test for ground with a digital multimeter. A test light might pull too much current and not light up if it's a very tiny bit of wire touching. A multimeter will definitely show ANY ground on either of those wire.
So before calling out your tuner, I'd check the harness and check the coolant temp sensor. A quick and easy way to test the harness would be to unplug both trigger pins from the ECM, and test for ground with a digital multimeter. A test light might pull too much current and not light up if it's a very tiny bit of wire touching. A multimeter will definitely show ANY ground on either of those wire.
I will test the harness and temp sensor soon. The doner Tahoe was in very good shape but doesn’t mean it was previously in an accident. I will have to find my notes (they are packed somewhere since I just moved) and check which trigger pins go to which color ecm connector and pin location. I believe it’s pins 42 and 38 but can’t remember which color ecm connector and wire to pin location. Do you remember off hand what trigger wire to what number pin and pin location to color connector? Thank you for all of the info. I appreciate it!
OP
OP
Dantheman-2003
Full Access Member
All: Can’t remember if I already provided an update, but my E-fan install was successful. Pulled my OEM harness out of my 05 Yukon and installed it in my 03 Tahoe. Thanks to all the support here on the thread. Scotty is the E-fan man! I’ve been up and running for several months, tuned, re-geared and running strong with E-fan setup.
Thanks to all.
Dan
Thanks to all.
Dan
