how do ppl convert belt-driven fan to electric fan on 99-04 GMT 800 tr

[tonyghkbve]

I see some people retrofit electric fans on 99-04 GMT 800 pickups. Electric fan is much better since the engine doesn't have to waste power to drive the cooling fan. What is involved in all this conversion? Is it possible to use the 05-07 GMT 800 cooling fan unit and put it on?

[Chris]

You can use those fans, but you need the 05-06 radiator. It is wider. You need the computer tuned to turn fans on at certain temps, a harness, and tools.

[nickvrebel]

The cleanest way is to use 05+ fans with a custom harness and tune to run them. For my 03 Silverado I had fans from a LS1 car with a custom harness and I controlled them with HP Tuners.

 

 

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[txab]

http://www.truckmodcentral.com/forums/showthread.php?t=17717&highlight=electric+fans

[tonyghkbve]

Doesn't sound too difficult. What programmer do you used to retrofit 05 radiator plus cooling fans to work in 99-04 Silverado?

[waumo1]

Remember electric fans don't run for free. Your engine has to supply the power to generate the electric the fan uses. If you already have a clutch type fan, I doubt the conversion makes economic sense.

[Chris]

Black Bear performance can take care of that

 

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[Badass69]

2003 and 2004 are the simplest by far as the PCM is the same essentially as the 05-07's. The difference is having pressure transducers for both high and low on the a/c. You can simply tap the Green connector on pin 33 with the green trigger and the blue connector on pin 42 with the blue wire.

 

The factory e fan harness is by far the cleanest..... so wrecking yard or you can purchase it new still and the part number is 15912597. It is included as part of the headlight harness which you can strip it out of. If you want the whole route you need the piece GM added to the harness of the PCM.. just a 2 pin connector with your two trigger wires. Easy to make though, or just cut off the connector from the main harness and extend the 2 pins that go to the pcm.

 

The aftermarket harness's are okay...... but the GM one is a nice piece with better relay life.

 

You of course have to tune the PCM to tell it to trigger the fans and then set your on and off points for temperature, a/c, vehicle speed etc. I self tune ( efi live) but Blackbear as an example enables the fans in all of his tunes.....

 

Rad wise it's if you have a 28" rad you need to get the 34". Since I play only with HD truck I don't need to worry about that. Honestly just pull the shround and clutch fan and drop it right in. You also need a second set of the exact same bolts that hold the rad to the core support. The clutch fan shroud is bolted in a different spot on the support with smaller bolts.

 

Another word is any fans from 2005 all the way to present year truck fit....... So I have the 7 and 9 blade combo used in a 2011+ 6.2 truck. They are cheap to buy new... like $160 a set cheap so don't fall for this expensive used BS people try and pull on these boards.

 

Upgrading the alternator is really a must. I have the 145's on my trucks as GM did factory.

 

Losing that junk clutch fan was really nice for me. I have a lot of winter and that is where e fans really shine. That stupid frozen viscous clutch is useless in the cold..... Any clutch fan unit would cool off when idling in freezing temperatures no doubt because the clutch fan is literally frozen on and the wind chill it creates under the hood is pretty bad. Now with e fans in that same temp with the same truck it can idle all day long and stay warm enough the fans will cycle now and again to keep it in temp...... and never lose a degree below the thermostats setpoint. That alone was worth the change. It's nice in summer for a/c performance especially anywhere near idle where the clutch fan is also useless. And I am sorry to the nay sayers but my two fans on high which now cover the entire rad.... move way more air across than that clutch fan could ever hope too. One fan alone is about the same size as the oem cluch unit was.

[MikeNH]

Remember electric fans don't run for free. Your engine has to supply the power to generate the electric the fan uses. If you already have a clutch type fan, I doubt the conversion makes economic sense.

 

 

 

I'd think the drag of the clutch fan is far worse than an alternator pulling a load. And regardless the gain in AC performance at low speeds is worth it- my 2011 will freeze you out whereas my 2003 barely worked when stopped.

[Tom Lockwood]

One participant said that the radiator used with electric cooling fans is wider. That is not true. Both  radiators (clutch vs electric) are 864 mm wide.

The radiator used with electric fans is thicker, adding to the capacity.

Another says that the electric fans use energy as well, so likely no gain vs clutch. The clutch fan consumes energy constantly, whether engaged or not. The electric fans use no energy when they are off (a typical operating condition). The difference is an actual 0.25 mpg.

[PinnacleHD]

I realize this is an old thread but I’m doing this conversion on my 04 and I’ve got an 06 donor vehicle. Am I able to just take the PCM out of the 06 and put it in the 04 Instead of getting it reprogrammed?

[SierraHD17]

Older non electric fan trucks came with 28 inch wide radiators and all with electric are a 34" core.  The 34" core was an option in 99 to 04 but not standard equipment.  Is what it is.

 

Swapping PCMs requires a BCM security relearn to do.  I'm not 100% if an 06 will swap in place of an 04 ( 06 uses a different tac module, throttle body and gas pedal so pin placement may change) but 05 should work okay and those have e fans. 

 

If not tuning works good too.