questions re electric fan harness: Nelson vs Black Bear

[heftylefty58]

Next year, I plan to have my 2003 Yukon Denali tuned by Black Bear Performance. In the meantime, I'm trying to figure out which harness I should go with for my electric fan upgrade.

Can anyone confirm what the differences are between Nelson's harness and Blackbear's harness?

I could be wrong, but here's my impression: Blackbear's harness will not be able to control my electric fans until Justin tunes my PCM. Nelson's installation instructions imply that no tune is necessary when using their harness.

At this point, I'm wondering if I should go ahead and install Nelson's harness/efans now, or if I should hold off and install Blackbear's harness/efans after my tune.

Any/all thoughts are appreciated.

 

[BlizzardX23]

Good question... I donno either

I have my brand new OEM electric fans just hanging up in the garage because I have no harness...I need to get a harness this year though since the tune will be in Jan

 

[vatahoelt]

Good question... I donno either

I have my brand new OEM electric fans just hanging up in the garage because I have no harness...I need to get a harness this year though since the tune will be in Jan

your oem fans didn't come with a harness? or is it extra?

 

[OmarR]

For 03+, both Blackbear and Nelson's will require you to have your PCM pins 33 and 42 turned on thru a tune.

If Nelson's website is unclear about this, you could always email them to make sure. But they both work the same way.

I personally went with the factory harness, but it's a little more pricey.

 

[heftylefty58]

For 03+, both Blackbear and Nelson's will require you to have your PCM pins 33 and 42 turned on thru a tune.

If Nelson's website is unclear about this, you could always email them to make sure. But they both work the same way.

I personally went with the factory harness, but it's a little more pricey.

Thanks Omar! I just sent an email to Nelson Performance to confirm.

I have another dumb question:

Does anyone know if there is any harm driving around with pins 33 & 42 turned on withOUT my new efan/harness being hooked up? I'm wondering how long can I drive around with pins 33 & 42 turned on before I absolutely have to install my new efan/harness.

 

[NyteSnyper]

I wouldnt think it would harm anything, there isnt a wire going to 42 at all then its covered by the plastic connector. BTW, when I installed efans in my 04 Silv. with the nelson harness, I had to turn on pin 42 for them to work (I have HPTuners).

 

[heftylefty58]

Thanks for all the feedback! I sent an email Nelson Performance last night, and received a prompt response. Here's my attempt to summarize their answer to my question:

• In order for the efans to operate correctly with their harness, the PCM needs to be tuned (ie, Pin42 must be activated).
• If you have already installed the efans/harness and can't tune your PCM any time soon, then the efans won't run unless you install a manual wire. Note that this will also require you to toggle it on and off in order to get the fans to run.

Here's their full reply:

Our fan harness allows you to install three types of fans; the LS1 F-body fans, GM OEM (05+ GM trucks) fans, and dual, universal fans, such as the Flex a Lite fans into your 99+ GM truck/suv.

Keep in mind that in order for the fans to operate correctly, Pin42 must be activated to support fan function. The PCM can be substituted for a manual wire, however, you will have to toggle it on and off in order for the fans to operate.

Every fan harness is designed to blend in with the factory harness; they are covered in automotive loom.

Each terminal and connection is crimped and soldered to resist contamination and from working loose.

High amperage relays are used to handle the demanding loads of large fans.

Installation is a very easy and includes every part needed for a smooth install.

The operation is similar to the factory setup. Here's how it works:

The PCM is setup to power both fans on low speed when a desired temperature setting is reached.

One fan will power on high when the A/C clutch is activated.

If the PCM and A/C signals are activated, then both fans will power on high.

In order to purchase the harness, please give us a call or send $89 + $10shipping to [email protected]

We also have an online form you can fill out; once received you will receive a confirmation email within 24hrs.

We can also offer a PCM swap for those who do not have the ability to activate the fans or do not have a shop near by that has the ability.

The cost is $55 for the OEM flash of your VIN and GM's latest calibration, $35 for the activation, plus shipping.

Thank you

 

[OmarR]

Does anyone know if there is any harm driving around with pins 33 & 42 turned on withOUT my new efan/harness being hooked up?

No harm. I went for 15 months until I finally got around to buying and installing the electric fans and harness.

 

[vjr021]

I have two fans from a Lambo Murcielago that I have been holding on to, I might look into tryign to get them to fit in the Denali...

 

[blueflamed03]

had mine pins turned on (with no fans) earlier this summer by Justin at Black Bear....if your getting a BB tune, why not get their harness?